diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 0000000..a380554
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1,10 @@
+**/*.o
+**/*.a
+**/*.dSYM
+.git
+.github
+.claude/
+CLAUDE.md
+docs/
+devtools/
+*~
diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 0000000..f0dd1a8
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,16 @@
+FROM ubuntu:24.04
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        gcc \
+        libc6-dev \
+        make \
+        bison \
+        flex \
+        libx11-dev \
+        libxt-dev \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /build
+COPY . .
+RUN find . -name '*.o' -delete && find . -name '*.a' -delete
+RUN cd ESPS/general && ./SETUP -p /usr/esps && ./ESPS_INSTALL
diff --git a/ESPS/ATT/libsig/Makefile b/ESPS/ATT/libsig/Makefile
index 7fb9d93..bef523d 100644
--- a/ESPS/ATT/libsig/Makefile
+++ b/ESPS/ATT/libsig/Makefile
@@ -18,7 +18,7 @@
 
 
 INC = ../waves/src/h
-CFLAGS = -g -I$(INC) -I$(XVIEW_INC) -DHEAD_STANDALONE -DFOR_XVIEW $(PROGCFLAGS) 
+CFLAGS = -g -I$(INC) -DHEAD_STANDALONE $(PROGCFLAGS)
 LPATH = $(SPSDIR)
 LBIN = $(BINDIR)
 LIB = $(WAVESDIR)/xlibsig.a
diff --git a/ESPS/general/SETUP b/ESPS/general/SETUP
index 659abb8..19d1f1f 100755
--- a/ESPS/general/SETUP
+++ b/ESPS/general/SETUP
@@ -398,13 +398,12 @@ here=`pwd`
 #
 if test $MACH = LINUX
  then
-  ANSI_CC="gcc -ansi"
-  ELM_CC="gcc -DANSI_C"
+  CC="gcc -fno-builtin -std=gnu89 -fcommon -D_FORTIFY_SOURCE=0 -Wno-implicit-function-declaration -Wno-implicit-int -Wno-return-type -Wno-int-conversion -Wno-incompatible-pointer-types -Wno-parentheses -Wno-dangling-else -Wno-format"
+  ANSI_CC="gcc -std=gnu89 -fcommon -DANSI_C -D_FORTIFY_SOURCE=0 -Wno-implicit-function-declaration -Wno-implicit-int -Wno-return-type -Wno-int-conversion"
+  ELM_CC="gcc -std=gnu89 -fcommon -DANSI_C -D_FORTIFY_SOURCE=0 -Wno-implicit-function-declaration -Wno-implicit-int -Wno-return-type -Wno-int-conversion"
   DEFINES="-DLINUX_OR_MAC"
-#Xorg libraries that used to be in /usr/X11R6/lib are now in /usr/lib on
-#Fedora Core 5.
-  X_LIB="-L/usr/X11R6/lib -L/usr/lib -lX11"
-  X_INC="/usr/X11R6/include"
+  X_LIB="-lX11"
+  X_INC="/usr/include"
   X_R7_LIBS="-lXdmcp -lXau"
   WINLIBS="$X_LIB -lpthread"
   X_UTIL="-lutil"
@@ -417,15 +416,23 @@ if test $MACH = LINUX
   ln -s makefile.linux makefile
   chmod a+w makefile
   cd $here
+  # GNU ld processes archives left-to-right and only extracts objects that
+  # resolve currently-undefined symbols. The ESPS header and main libraries
+  # have circular dependencies, so repeat both to give the linker enough
+  # passes to resolve everything.
+  SPSLIB=${EXV_LIB}" "${LIBDIR}/${EHDRLIB}" "${LIBDIR}/${LIBNAME}" "${LIBDIR}/${EHDRLIB}" "${LIBDIR}/${LIBNAME}
+  WSPSLIB=${EXV_LIB}" "${LIBDIR}/${WHDRLIB}" "${LIBDIR}/${LIBNAME}" "${LIBDIR}/${WHDRLIB}" "${LIBDIR}/${LIBNAME}
+  NSPSLIB=${EXV_LIB}" "${LIBDIR}/${NHDRLIB}" "${LIBDIR}/${LIBNAME}" "${LIBDIR}/${NHDRLIB}" "${LIBDIR}/${LIBNAME}
+  SSPSLIB=${EXV_LIB}" "${LIBDIR}/${SHDRLIB}" "${LIBDIR}/${LIBNAME}" "${LIBDIR}/${SHDRLIB}" "${LIBDIR}/${LIBNAME}
 fi
 ################################################################################
 # Machine dependent defines for MACOS-X:
 #
 if test $MACH = MACOS
  then
-  CC="gcc -fno-builtin" \
-  ANSI_CC="gcc -ansi -DANSI_C"
-  ELM_CC="gcc -DANSI_C"
+  CC="gcc -fno-builtin -std=gnu89 -D_FORTIFY_SOURCE=0 -Wno-implicit-function-declaration -Wno-implicit-int -Wno-return-type -Wno-int-conversion -Wno-incompatible-pointer-types -Wno-parentheses -Wno-dangling-else -Wno-format"
+  ANSI_CC="gcc -std=gnu89 -DANSI_C -D_FORTIFY_SOURCE=0 -Wno-implicit-function-declaration -Wno-implicit-int -Wno-return-type -Wno-int-conversion"
+  ELM_CC="gcc -std=gnu89 -DANSI_C -D_FORTIFY_SOURCE=0 -Wno-implicit-function-declaration -Wno-implicit-int -Wno-return-type -Wno-int-conversion"
   DEFINES="-DLINUX_OR_MAC"
   X_LIB="-L/usr/X11R6/lib -L/usr/lib -lX11"
   X_INC="/usr/X11R6/include"
@@ -1179,8 +1186,14 @@ export LIBMV AUDIOLIB
 if test $MACH = MACOS
  then
 # This is mostly for the MACOS installation to pick up the little Mplay and Mrecord scripts.
-  cp -f ./scripts/* $BINDIR
-  cp -f ../../macAudio/build/audioM $BINDIR
+  if test -d ./scripts; then
+    cp -f ./scripts/* $BINDIR
+  fi
+  if test -f ../../macAudio/build/audioM; then
+    cp -f ../../macAudio/build/audioM $BINDIR
+  else
+    echo "Warning: macAudio/build/audioM not found, skipping audio binary install."
+  fi
 fi
 
 SPSLIB2=$SPSLIB
@@ -1223,16 +1236,20 @@ elif test $MACH = LINUX -o $MACH = MACOS; then
         XVIEW_LIB="-Wl,-Bstatic "$XVIEW_LIB" -Wl,-Bdynamic"
     fi
   else
-    echo "Error: Xview libraries not found in linker path."; exit 1
+    echo "Warning: Xview libraries not found in linker path."
+    echo "GUI components (xwaves, etc.) will not be available."
+    XVIEW_LIB=""
   fi # [ -n "$XV_STAT_OR_DYN" ]
-XVIEW_LIB="$XVIEW_LIB $X_UTIL $WINLIBS"
+if [ -n "$XVIEW_LIB" ] ; then
+  XVIEW_LIB="$XVIEW_LIB $X_UTIL $WINLIBS"
+fi
 echo XVIEW_LIB is $XVIEW_LIB
 # Is there an xview directory in the include path?
   if echo "#include <xview/xview.h>" |cpp >/dev/null 2>&1 ; then
     echo "Xview include files present in include path, we don't need to add them"
   else
-    echo "Error: Xview include files not found in path,"; exit 1
-    echo "include directory"
+    echo "Warning: Xview include files not found in path."
+    echo "GUI components (xwaves, etc.) will not be available."
   fi
   XVIEW_INC="$SINCP"
 else
diff --git a/ESPS/general/other_includes/sphere/sphere.h b/ESPS/general/other_includes/sphere/sphere.h
index ede0c1a..ac614c5 100644
--- a/ESPS/general/other_includes/sphere/sphere.h
+++ b/ESPS/general/other_includes/sphere/sphere.h
@@ -32,7 +32,7 @@ extern "C" {
 #include <sp/wavpack/wavpack.h>
 #include <sp/version.h>
 
-#ifndef u_int
+#if !defined(u_int) && !defined(__APPLE__)
 #define u_int unsigned int
 #endif
 
diff --git a/ESPS/general/src/COMPILE b/ESPS/general/src/COMPILE
index f92ffe8..47acdfd 100755
--- a/ESPS/general/src/COMPILE
+++ b/ESPS/general/src/COMPILE
@@ -7,6 +7,8 @@ if echo $ua | grep -q -s "[Ll]inux" ; then export ARCH=linux
 elif echo $ua | egrep -q -s "[Dd]arwin|[Mm]ac" ; then export ARCH=mac
 fi
 current_dir=`pwd`
+# Ensure other_includes (sphere, pixrect headers) are in ESPS_BASE/include
+cp -r $current_dir/../other_includes/* $ESPS_BASE/include/ 2>/dev/null
 cd $current_dir/../h; emake clean; emake install $CLEAN; cd $current_dir
 if test x$1 = xlibs
  then
@@ -17,7 +19,14 @@ if test x$1 = xlibs
 	cd $current_dir
   cd lib_header; emake clean; emake install $CLEAN; cd $current_dir
   cd lib_sp; emake clean; emake install $CLEAN; cd $current_dir
-  cd libxv; emake clean; emake install $CLEAN; cd $current_dir
+  #cd libxv; emake clean; emake install $CLEAN; cd $current_dir
+  # Create empty libexv.a so components that reference EXV_LIB can link.
+  # macOS ar rejects archives with no members, so compile a dummy object.
+  echo "void __libexv_dummy(void){}" > /tmp/libexv_dummy.c
+  ${CC:-gcc} -c /tmp/libexv_dummy.c -o /tmp/libexv_dummy.o
+  ar rc $ESPS_BASE/lib/libexv.a /tmp/libexv_dummy.o
+  ranlib $ESPS_BASE/lib/libexv.a
+  rm -f /tmp/libexv_dummy.c /tmp/libexv_dummy.o
 fi
 cd utils; emake clean; emake install $CLEAN; cd $current_dir
 cd $current_dir/../man;  emake install
@@ -30,8 +39,8 @@ case `mach_type` in
 	SG)	AUDIO=sgaudio ;;
 esac
 # HERE IS WHERE XWAVES, ETC. GET MADE....
-cd ../../ATT ; emake clean; emake install $CLEAN;  cd $current_dir
-cd ${ARCH}_audio; emake clean; emake install $CLEAN; cd $current_dir
+#cd ../../ATT ; emake clean; emake install $CLEAN;  cd $current_dir
+#cd ${ARCH}_audio; emake clean; emake install $CLEAN; cd $current_dir
 cd acf; emake clean; emake install $CLEAN; cd $current_dir
 cd addclass; emake clean; emake install $CLEAN; cd $current_dir
 cd addfea; emake clean; emake install $CLEAN; cd $current_dir
@@ -63,9 +72,9 @@ cd ereverse; emake clean; emake install $CLEAN; cd $current_dir
 cd erlsupport; emake clean; emake install $CLEAN; cd $current_dir
 cd esps2mu; emake clean; emake install $CLEAN; cd $current_dir
 cd eversion; emake clean; emake install $CLEAN; cd $current_dir
-cd exprompt; emake clean; emake install $CLEAN; cd $current_dir
-cd expromptrun; emake clean; emake install $CLEAN; cd $current_dir
-cd fbuttons; emake clean; emake install $CLEAN; cd $current_dir
+#cd exprompt; emake clean; emake install $CLEAN; cd $current_dir
+#cd expromptrun; emake clean; emake install $CLEAN; cd $current_dir
+#cd fbuttons; emake clean; emake install $CLEAN; cd $current_dir
 cd fea2mat; emake clean; emake install $CLEAN; cd $current_dir
 cd fea_deriv; emake clean; emake install $CLEAN; cd $current_dir
 cd fea_edit; emake clean; emake install $CLEAN; cd $current_dir
@@ -87,13 +96,13 @@ cd frame; emake clean; emake install $CLEAN; cd $current_dir
 cd genplot; emake clean; emake install $CLEAN; cd $current_dir
 cd get_esps_base; emake clean; emake install $CLEAN; cd $current_dir
 cd getparam; emake clean; emake install $CLEAN; cd $current_dir
-cd gpstohp; emake clean; emake install $CLEAN; cd $current_dir
+#cd gpstohp; emake clean; emake install $CLEAN; cd $current_dir
 cd hditem; emake clean; emake install $CLEAN; cd $current_dir
 cd hdshrink; emake clean; emake install $CLEAN; cd $current_dir
 cd his; emake clean; emake install $CLEAN; cd $current_dir
 cd igenplot; emake clean; emake install $CLEAN; cd $current_dir
 cd iir_filt; emake clean; emake install $CLEAN; cd $current_dir
-cd image; emake clean; emake install $CLEAN; cd $current_dir
+#cd image; emake clean; emake install $CLEAN; cd $current_dir
 cd imlplot; emake clean; emake install $CLEAN; cd $current_dir
 cd impulse_rs; emake clean; emake install $CLEAN; cd $current_dir
 cd larcbk2rc; emake clean; emake install $CLEAN; cd $current_dir
@@ -103,7 +112,7 @@ cd lpcsynt; emake clean; emake install $CLEAN; cd $current_dir
 cd make_sd; emake clean; emake install $CLEAN; cd $current_dir
 cd mat2fea; emake clean; emake install $CLEAN; cd $current_dir
 cd mbrot; emake clean; emake install $CLEAN; cd $current_dir
-cd mbuttons; emake clean; emake install $CLEAN; cd $current_dir
+#cd mbuttons; emake clean; emake install $CLEAN; cd $current_dir
 cd me_sgram; emake clean; emake install $CLEAN; cd $current_dir
 cd me_spec; emake clean; emake install $CLEAN; cd $current_dir
 cd mergefea; emake clean; emake install $CLEAN; cd $current_dir
@@ -114,7 +123,7 @@ cd mux; emake clean; emake install $CLEAN; cd $current_dir
 cd notch_filt; emake clean; emake install $CLEAN; cd $current_dir
 cd pen; emake clean; emake install $CLEAN; cd $current_dir
 cd playtest; emake clean; emake install $CLEAN; cd $current_dir
-cd plot3d; emake clean; emake install $CLEAN; cd $current_dir
+#cd plot3d; emake clean; emake install $CLEAN; cd $current_dir
 cd plotfield; emake clean; emake install $CLEAN; cd $current_dir
 cd pplain; emake clean; emake install $CLEAN; cd $current_dir
 cd psps; emake clean; emake install $CLEAN; cd $current_dir
@@ -125,7 +134,7 @@ cd rem_dc; emake clean; emake install $CLEAN; cd $current_dir
 cd sdcomp; emake clean; emake install $CLEAN; cd $current_dir
 cd sdtofea; emake clean; emake install $CLEAN; cd $current_dir
 # cd select; emake clean; emake install $CLEAN; cd $current_dir
-cd send_xwaves; emake clean; emake install $CLEAN; cd $current_dir
+#cd send_xwaves; emake clean; emake install $CLEAN; cd $current_dir
 cd setmax; emake clean; emake install $CLEAN; cd $current_dir
 cd setrange; emake clean; emake install $CLEAN; cd $current_dir
 cd sfconvert; emake clean; emake install $CLEAN; cd $current_dir
@@ -146,18 +155,18 @@ cd vqclassify; emake clean; emake install $CLEAN; cd $current_dir
 cd vqdst; emake clean; emake install $CLEAN; cd $current_dir
 cd window; emake clean; emake install $CLEAN; cd $current_dir
 cd wmse_filt; emake clean; emake install $CLEAN; cd $current_dir
-cd wsystem; emake clean; emake install $CLEAN; cd $current_dir
-cd xacf; emake clean; emake install $CLEAN; cd $current_dir
+#cd wsystem; emake clean; emake install $CLEAN; cd $current_dir
+#cd xacf; emake clean; emake install $CLEAN; cd $current_dir
 #cd xpz; emake clean; emake install $CLEAN; cd $current_dir
-cd xtext; emake clean; emake install $CLEAN; cd $current_dir
+#cd xtext; emake clean; emake install $CLEAN; cd $current_dir
 cd zcross; emake clean; emake install $CLEAN; cd $current_dir
 cd zero_pole; emake clean; emake install $CLEAN; cd $current_dir
 cd zero_pad; emake clean; emake install $CLEAN; cd $current_dir
 cd e2sphere; emake clean; emake install $CLEAN; cd $current_dir
 cd filter2; emake clean; emake install $CLEAN; cd $current_dir
-cd formsy; emake clean; emake install $CLEAN; cd $current_dir
-cd ps_ana; emake clean; emake install $CLEAN; cd $current_dir
-cd epochs; emake clean; emake install $CLEAN; cd $current_dir
+#cd formsy; emake clean; emake install $CLEAN; cd $current_dir
+#cd ps_ana; emake clean; emake install $CLEAN; cd $current_dir
+#cd epochs; emake clean; emake install $CLEAN; cd $current_dir
 cd feaop; emake clean; emake install $CLEAN; cd $current_dir
 cd lp_syn; emake clean; emake install $CLEAN; cd $current_dir
 cd ps2frame; emake clean; emake install $CLEAN; cd $current_dir
@@ -170,7 +179,7 @@ cd win_filt; emake clean; emake install $CLEAN; cd $current_dir
 # cd meter; emake clean; emake install $CLEAN; cd $current_dir
 cd get_resid; emake clean; emake install $CLEAN; cd $current_dir
 cd zst; emake clean; emake install $CLEAN; cd $current_dir
-cd xfir_filt; emake clean; emake install $CLEAN; cd $current_dir
+#cd xfir_filt; emake clean; emake install $CLEAN; cd $current_dir
 cd ebanner; emake clean; emake install $CLEAN; cd $current_dir
 # cd rasta_plp; emake clean; emake install $CLEAN; cd $current_dir
 cd cepsyn; emake clean; emake install $CLEAN; cd $current_dir
diff --git a/ESPS/general/src/addfeahd/addfeahd.c b/ESPS/general/src/addfeahd/addfeahd.c
index da98639..f1d6a44 100644
--- a/ESPS/general/src/addfeahd/addfeahd.c
+++ b/ESPS/general/src/addfeahd/addfeahd.c
@@ -378,7 +378,7 @@ char  **argv;
 
     if(foreign_header) {
     	*add_genhd_l("foreign_hd_length", (long *)NULL, 1, out_hd) = skip;
-#if !defined(IBM_RS6000) && !defined(DS3100) && !defined(SG) && !defined(HP400) && !defined(M5600) && !defined(OS5) && !defined(LINUX)
+#if !defined(IBM_RS6000) && !defined(DS3100) && !defined(SG) && !defined(HP400) && !defined(M5600) && !defined(OS5) && !defined(LINUX) && !defined(LINUX_OR_MAC)
 	(char *)foreign_hd_ptr = malloc((unsigned)skip);
 #else
 	foreign_hd_ptr = malloc((unsigned)skip);
diff --git a/ESPS/general/src/btosps/btosps.c b/ESPS/general/src/btosps/btosps.c
index bcc99ac..d45bc1f 100644
--- a/ESPS/general/src/btosps/btosps.c
+++ b/ESPS/general/src/btosps/btosps.c
@@ -279,7 +279,7 @@ char  **argv;
 
     if(foreign_header) {
     	*add_genhd_l("foreign_hd_length", (long *)NULL, 1, oh) = skip;
-#if defined(IBM_RS6000) || defined(DS3100) || defined(SG) || defined(HP400) || defined(M5600) || defined(OS5) || defined(LINUX)
+#if defined(IBM_RS6000) || defined(DS3100) || defined(SG) || defined(HP400) || defined(M5600) || defined(OS5) || defined(LINUX) || defined(LINUX_OR_MAC)
 	foreign_hd_ptr = malloc((unsigned)skip);
 #else
 	(char *)foreign_hd_ptr = malloc((unsigned)skip);
diff --git a/ESPS/general/src/lib/makefile b/ESPS/general/src/lib/makefile
index 51b3b8d..98b65bb 120000
--- a/ESPS/general/src/lib/makefile
+++ b/ESPS/general/src/lib/makefile
@@ -1 +1 @@
-makefile.linux
\ No newline at end of file
+makefile.mac
\ No newline at end of file
diff --git a/ESPS/general/src/lib/makefile.mac b/ESPS/general/src/lib/makefile.mac
index b64af02..ffaf7fb 100644
--- a/ESPS/general/src/lib/makefile.mac
+++ b/ESPS/general/src/lib/makefile.mac
@@ -29,7 +29,7 @@ tmpfile.o typeconver.o uniq_name.o updatewave.o vqsupport.o \
 execcom.o tempname.o feadstsupp.o isespsfile.o \
 pr_farray.o typesiz.o findespsfi.o getespsbas.o sendwaves.o feafiltsupp.o \
 buildespsp.o convertlab.o trngswitch.o malloc.o ereader.o wavesshow.o \
-is_numeric.o xsend.o audio_.o  audio_mac.o usleep.o eddy.o
+is_numeric.o audio_.o  audio_mac.o usleep.o eddy.o
 
 SRCS =	\
 addstr.c anafeasupp.c atoarray.c atoh.c copy_fea_rec.c \
@@ -47,7 +47,7 @@ tmpfile.c typeconver.c uniq_name.c updatewave.c vqsupport.c \
 pr_farray.c typesiz.c \
 findespsfi.c getespsbas.c sendwaves.c feafiltsupp.c buildespsp.c \
 convertlab.c trngswitch.c malloc.c ereader.c wavesshow.c \
-is_numeric.c xsend.c audio_.c  usleep.c eddy.c
+is_numeric.c audio_.c  usleep.c eddy.c
 
 $(LIBDIR)/$(LIBNAME):	$(OBJS)
 	ar rv $(LIBDIR)/$(LIBNAME) $?
@@ -79,10 +79,6 @@ updatewave.o:	$(SINC)/esps.h $(SINC)/unix.h
 miio.o:		$(SINC)/esps.h $(SINC)/header.h
 is_complex.o:	$(SINC)/esps.h $(SINC)/fea.h
 fea_compat.o:	$(SINC)/esps.h $(SINC)/fea.h
-xsend.o:	$(SINC)/xwaves_ipc.h 
-	        $(CC) -I$(X_INC) $(CFLAGS) -c xsend.c
-
-
 install:	$(LIBDIR)/$(LIBNAME)
 		rm -f $(SPSDIR)/src_examples/lib/feaspecsupp.c
 		cp feaspecsupp.c $(SPSDIR)/src_examples/lib/feaspecsupp.c
diff --git a/ESPS/general/src/lib_header/makefile b/ESPS/general/src/lib_header/makefile
index 8684cf6..b19c7d8 100644
--- a/ESPS/general/src/lib_header/makefile
+++ b/ESPS/general/src/lib_header/makefile
@@ -61,6 +61,7 @@ esps/headers.o:  license.c headers.o $(SINC)/header.h  \
 			$(SINC)/esps.h   sphere.o \
 			$(ESIGNAL_LIB)/libesignal.a esignal_fea.o  pc_wav.o
 		$(ELM_CC) -c  $(CFLAGS)   -DESPS_PROG $(NO_LIC) license.c
+		mkdir -p esps
 		mv license.o esps
 		ld -o esps/headers.o -r headers.o  esps/license.o \
 		  sphere.o \
@@ -71,6 +72,7 @@ waves/headers.o: license.c headers.o  $(SINC)/header.h   \
 			$(SINC)/esps.h   sphere.o \
 			$(ESIGNAL_LIB)/libesignal.a esignal_fea.o  pc_wav.o
 		$(ELM_CC) -c $(OFLAGS) $(CFLAGS) -I$(XVIEW_INC) -DWAVES_PROG $(NO_LIC) license.c
+		mkdir -p waves
 		mv license.o waves
 		ld -o waves/headers.o -r headers.o waves/license.o \
 		sphere.o \
@@ -81,6 +83,7 @@ ers/headers.o: license.c headers.o  $(SINC)/header.h   \
 			$(SINC)/esps.h sphere.o \
 			$(ESIGNAL_LIB)/libesignal.a esignal_fea.o  pc_wav.o
 		$(ELM_CC) -c $(CFLAGS) -I$(XVIEW_INC) -DWAVES_PROG -DERS_PROG $(NO_LIC) license.c
+		mkdir -p ers
 		mv license.o ers
 		ld -o ers/headers.o -r headers.o ers/license.o \
 		sphere.o \
diff --git a/ESPS/general/src/lib_header/sphere2.6/include/sp/sphere.h b/ESPS/general/src/lib_header/sphere2.6/include/sp/sphere.h
index ede0c1a..ac614c5 100644
--- a/ESPS/general/src/lib_header/sphere2.6/include/sp/sphere.h
+++ b/ESPS/general/src/lib_header/sphere2.6/include/sp/sphere.h
@@ -32,7 +32,7 @@ extern "C" {
 #include <sp/wavpack/wavpack.h>
 #include <sp/version.h>
 
-#ifndef u_int
+#if !defined(u_int) && !defined(__APPLE__)
 #define u_int unsigned int
 #endif
 
diff --git a/ESPS/general/src/lib_header/sphere2.6/src/bin/Makefile b/ESPS/general/src/lib_header/sphere2.6/src/bin/Makefile
index f8e80eb..8edba67 100644
--- a/ESPS/general/src/lib_header/sphere2.6/src/bin/Makefile
+++ b/ESPS/general/src/lib_header/sphere2.6/src/bin/Makefile
@@ -46,7 +46,7 @@ INCLUDE = $(PROJECT_ROOT)/include
 LIBDIR	= $(LIBS)
 
 CFLAGS	= -I$(INCLUDE) -L$(LIBDIR) $(LOCAL_CFLAGS)
-CC	= gcc -ansi 
+CC	= gcc -std=gnu89 -D_FORTIFY_SOURCE=0 -Wno-implicit-function-declaration -Wno-implicit-int -Wno-return-type
 INSTALL	= install -c -s -m 755
 
 MAKEFILE	= Makefile
diff --git a/ESPS/general/src/lib_header/sphere2.6/src/lib/sp/Makefile b/ESPS/general/src/lib_header/sphere2.6/src/lib/sp/Makefile
index 7a217a7..502cc1e 100644
--- a/ESPS/general/src/lib_header/sphere2.6/src/lib/sp/Makefile
+++ b/ESPS/general/src/lib_header/sphere2.6/src/lib/sp/Makefile
@@ -52,7 +52,7 @@ LIBRY	= $(LIBRARY)
 
 CFLAGS	= -I$(INCLUDE) $(PROGCFLAGS) $(LOCAL_CFLAGS)
 #CFLAGS	= -I$(INCLUDE) $(LOCAL_CFLAGS)
-override CC	= gcc -ansi $(CFLAGS)
+override CC	= gcc -std=gnu89 -D_FORTIFY_SOURCE=0 -Wno-implicit-function-declaration -Wno-implicit-int -Wno-return-type $(CFLAGS)
 
 MAKEFILE	= Makefile
 .PRECIOUS: $(MAKEFILE)
diff --git a/ESPS/general/src/lib_header/sphere2.6/src/lib/sp/fixio.c b/ESPS/general/src/lib_header/sphere2.6/src/lib/sp/fixio.c
index aeaf176..8d55e3e 100644
--- a/ESPS/general/src/lib_header/sphere2.6/src/lib/sp/fixio.c
+++ b/ESPS/general/src/lib_header/sphere2.6/src/lib/sp/fixio.c
@@ -8,6 +8,7 @@
 
 # include <stdio.h>
 # include <stdlib.h>
+# include <unistd.h>
 /* Changed by Jon Fiscus */
 # include <util/fob.h>
 # include <sp/shorten/shorten.h>
diff --git a/ESPS/general/src/lib_header/sphere2.6/src/lib/util/Makefile b/ESPS/general/src/lib_header/sphere2.6/src/lib/util/Makefile
index 4033020..098a364 100644
--- a/ESPS/general/src/lib_header/sphere2.6/src/lib/util/Makefile
+++ b/ESPS/general/src/lib_header/sphere2.6/src/lib/util/Makefile
@@ -51,7 +51,7 @@ OBJ	= cfg.o comments.o ds.o err_util.o fobops.o hist.o hsgetopt.o itoa.o maldie.
 LIBRY	= $(LIBRARY)
 
 CFLAGS	= -I$(INCLUDE) $(LOCAL_CFLAGS)
-CC	= gcc -ansi $(CFLAGS)
+CC	= gcc -std=gnu89 -D_FORTIFY_SOURCE=0 -Wno-implicit-function-declaration -Wno-implicit-int -Wno-return-type $(CFLAGS)
 
 MAKEFILE	= Makefile
 .PRECIOUS: $(MAKEFILE)
diff --git a/ESPS/general/src/lib_sp/vqdesign.c b/ESPS/general/src/lib_sp/vqdesign.c
index e162c19..c40e523 100644
--- a/ESPS/general/src/lib_sp/vqdesign.c
+++ b/ESPS/general/src/lib_sp/vqdesign.c
@@ -14,6 +14,7 @@
  * This function designs a full-search vector quantization codebook
 */
 #include <stdio.h>
+#include <stdlib.h>
 #include <esps/esps.h>
 #include <esps/fea.h>
 #include <esps/vq.h>
@@ -476,7 +477,7 @@ int *error;
  */
 {
     int i;
-    static first = 1;		    /*flag for first time through*/
+    static int first = 1;	    /*flag for first time through*/
     static float **newcodebook;	    /*storage for new codewords*/
     long n_tosplit;	    /*number of codewords to split*/
     long n_index;	    /*index for new codewords*/
diff --git a/ESPS/general/src/lib_sp/vqencode.c b/ESPS/general/src/lib_sp/vqencode.c
index 968b505..9407e27 100644
--- a/ESPS/general/src/lib_sp/vqencode.c
+++ b/ESPS/general/src/lib_sp/vqencode.c
@@ -21,6 +21,7 @@ static char *sccs_id = "@(#)vqencode.c	1.6	8/11/91 EPI";
 #endif
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <assert.h>
 #include <esps/esps.h>
 #define BIGDIST 1E20
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..3d5b3f5
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,7 @@
+# Build and test inside an Ubuntu 24.04 container (requires macOS container CLI)
+CONTAINER_TAG = esps-test
+
+.PHONY: container-test
+container-test:
+	container build --tag $(CONTAINER_TAG) --file Dockerfile .
+	container run --rm $(CONTAINER_TAG)
diff --git a/README.md b/README.md
index 0a9ed4d..0283fce 100644
--- a/README.md
+++ b/README.md
@@ -38,6 +38,87 @@ This project stands on work from many contributors across academia and industry,
 - [HTK history (CUED/HTK project mirror)](https://spandh.dcs.shef.ac.uk/ed_arena/htk/history.html)
 - [Upstream mirror repository: jeremysalwen/ESPS](https://github.com/jeremysalwen/ESPS)
 
+## Building on Modern macOS
+
+The ESPS codebase compiles on modern macOS (Apple clang 17, arm64) with minimal source changes. GUI/X11/audio components are excluded.
+
+### Quick Start
+
+```bash
+cd ESPS/general
+./SETUP                    # Generates emake, defaults install to /usr/esps
+./ESPS_INSTALL             # Builds and installs everything
+```
+
+Or to build into a custom directory:
+
+```bash
+cd ESPS/general
+./SETUP -p /path/to/install
+./ESPS_INSTALL
+```
+
+### What Gets Built
+
+- **154 compiled CLI utilities** (fft, lpcana, get_f0, frame, sgram, etc.) plus 12 macOS-specific audio scripts/binaries
+- **7 libraries**: `libespsg.a`, `libhdre.a`, `libhdrw.a`, `libhdrs.a`, `libhdrn.a`, `libesignal.a`, `libexv.a`
+
+### Excluded Components
+
+The following components require X11/XView/audio hardware not available on modern macOS and are skipped:
+
+libxv, xwaves (ATT), audio, image, formsy, ps_ana, gpstohp, exprompt, expromptrun, fbuttons, mbuttons, plot3d, send_xwaves, wsystem, xacf, xtext, epochs, xfir_filt, xpz
+
+### Changes Required for macOS Compilation
+
+All changes are minimal — only what the compiler requires:
+
+**Build system:**
+- `SETUP` — C89 compatibility flags (`-std=gnu89`, `-Wno-implicit-*`), non-fatal XView detection, guarded macAudio copy
+- `COMPILE` — Copy `other_includes` before build, comment out X11/GUI/HP components
+- `lib/makefile` — Remove X11-dependent `xsend.o` from library objects
+- `ATT/libsig/Makefile` — Remove XView dependency
+- `lib_header/makefile` — Add `mkdir -p` for build subdirectories
+- sphere2.6 Makefiles — Replace `gcc -ansi` with `gnu89` + warning suppression
+
+**Source code (6 files, compiler-required only):**
+- `sphere.h` — Guard `u_int` macro with `__APPLE__` to avoid typedef conflict
+- `fixio.c` — Add `#include <unistd.h>` for `swab()` declaration
+- `vqdesign.c` — Add `#include <stdlib.h>`, fix implicit int declaration
+- `vqencode.c` — Add `#include <stdlib.h>` for `exit()` declaration
+- `addfeahd.c`, `btosps.c` — Add `LINUX_OR_MAC` to platform guards for lvalue cast
+
+## Building on Linux (Ubuntu 24.04)
+
+ESPS also compiles on Ubuntu 24.04 (GCC 13, arm64/x86_64). A Dockerfile is provided for containerized builds.
+
+### Container Build (from macOS)
+
+Requires Apple's [`container`](https://github.com/apple/container) CLI:
+
+```bash
+make container-test
+```
+
+This builds ESPS inside an Ubuntu 24.04 container and produces **154 CLI utilities** (the same compiled programs as macOS; the 12 extra on macOS are platform-specific audio shell scripts).
+
+### Native Linux Build
+
+```bash
+# Install dependencies
+sudo apt-get install gcc libc6-dev make bison flex libx11-dev libxt-dev
+
+cd ESPS/general
+./SETUP -p /usr/esps
+./ESPS_INSTALL
+```
+
+### Key Linux Adaptations
+
+- `SETUP` — GCC flags: `-std=gnu89 -fcommon`, warning suppressions for legacy C, architecture-agnostic X11 library path
+- `SETUP` — Library link order repeats `libhdre.a`/`libespsg.a` to resolve circular dependencies with GNU ld (which processes archives in a single left-to-right pass, unlike macOS ld)
+- `COMPILE` — Creates `libexv.a` stub (XView disabled) using a dummy object for cross-platform `ar` compatibility
+
 ## Documentation
 
 - Live ESPS manual pages (upstream mirror): [jeremysalwen/ESPS `ESPS/general/man`](https://github.com/jeremysalwen/ESPS/tree/master/ESPS/general/man)