diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7d8ab13..61b9756 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -17,10 +17,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-20.04]
+        os: [ubuntu-22.04]
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Add 64-bit mingw-w64 to the PATH
       run: |
         echo "c:/msys64/bin;c:/msys64/mingw64/bin" >> $GITHUB_PATH
diff --git a/Makefile b/Makefile
index 05c23ee..048541b 100644
--- a/Makefile
+++ b/Makefile
@@ -38,7 +38,7 @@ DBG ?= -g
 OPTIM	?= -O2
 LFLAGS	= -t
 MYLDFLAGS	= $(LDFLAGS) $(DBG)
-MYCFLAGS	= $(OPTIM) $(DBG) $(CFLAGS) #-Wall
+MYCFLAGS	= -D_GNU_SOURCE $(OPTIM) $(DBG) $(CFLAGS) -ansi -Wall
 MYCXXFLAGS	= $(MYCFLAGS)
 LDADD	= -lstdc++ -lfl
 
@@ -46,8 +46,8 @@ LDADD	= -lstdc++ -lfl
 .SUFFIXES: .l .c .C .o
 
 GENSRCS	= mcstrip.c scan.c
-BLDSRCS	= lib.C main.C strerror.c
-MCSOBJS	= mcstrip.o strerror.o
+BLDSRCS	= lib.C main.C
+MCSOBJS	= mcstrip.o
 CYCOBJS	= main.o lib.o
 SCNOBJS	= scan.o
 
@@ -117,9 +117,7 @@ install-targets: make-install-dirs
 	$(INSTALL_DATA) mccabe.example $(DOCDIR)
 
 clean:
-	$(RM) cyclo mcstrip core *.o *~
+	$(RM) cyclo mcstrip core *.o *~ *.metrics *.preproc *.stripped
 
 cleanall: clean
 	$(RM) $(GENSRCS)
-
-
diff --git a/Makefile.test b/Makefile.test
index d270133..3a155ba 100644
--- a/Makefile.test
+++ b/Makefile.test
@@ -28,8 +28,8 @@ LDADD		= -lstdc++ -lfl
 .SUFFIXES: .o .c .C .l
 
 GENSRCS	= mcstrip.c scan.c
-BLDSRCS	= lib.C main.C strerror.c
-MCSOBJS	= mcstrip.o strerror.o
+BLDSRCS	= lib.C main.C
+MCSOBJS	= mcstrip.o
 CYCOBJS	= main.o lib.o
 SCNOBJS	= scan.o
 
diff --git a/list.h b/list.h
index 4b0deeb..a4f3fe8 100644
--- a/list.h
+++ b/list.h
@@ -24,7 +24,7 @@ third party claims) arising therefrom.
 // NOTE: _LIST_CLASSTYPE should be a text only single token.  Use typedefs.
 
 #ifndef COREDUMP
-#define COREDUMP  *((char*)0)=0  // causes a segmentation fault (only under UNIX)
+#define COREDUMP  *((volatile char*)0)=0  // causes a segmentation fault (only under UNIX)
 #endif
 
 #ifndef _LIST_CLASSNAME
diff --git a/mcstrip.l b/mcstrip.l
index e4ba9c1..dd0beb2 100644
--- a/mcstrip.l
+++ b/mcstrip.l
@@ -36,7 +36,6 @@ extern int getopt();
 #include <errno.h>
 #include <string.h>
 
-#include "strerror.h"
 
 /* this aren't declared yet */
 int yylex();
diff --git a/stack.h b/stack.h
index 865aac3..9bb7645 100644
--- a/stack.h
+++ b/stack.h
@@ -23,7 +23,7 @@ third party claims) arising therefrom.
 // NOTE: _STACK_TYPE should be a text only single token.  Use typedefs.
 
 #ifndef COREDUMP
-#define COREDUMP  *((char*)0)=0  // causes a segmentation fault (only under UNIX)
+#define COREDUMP  *((volatile char*)0)=0  // causes a segmentation fault (only under UNIX)
 #endif
 
 #ifndef _STACK_CLASSNAME