The following type of warning errors... ../../../source/tools/acpibin/abcompare.c: In function 'AbCompareAmlFiles': ../../../source/tools/acpibin/abcompare.c:462:5: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing] if (*((UINT32 *) Header1.Signature) != *((UINT32 *) Header2.Signature)) results from '-fstrict-aliasing', which is turned on by the specifying of the '-O2' optimization option. The solution is to turn it off by specifying '-fno-strict-aliasing'. At least, this appears to be a better solution than leaving it turned on but disabling the warnings by specifying '-Wstrict-aliasing=0'. diff -urN a/generate/unix/Makefile.config b/generate/unix/Makefile.config --- a/generate/unix/Makefile.config 2013-10-18 09:39:50.897095584 -0500 +++ b/generate/unix/Makefile.config 2013-10-18 09:46:03.069129999 -0500 @@ -125,7 +125,7 @@ # The _GNU_SOURCE symbol is required for many hosts. # OPT_CFLAGS ?= \ - -O2 -D_FORTIFY_SOURCE=2\ + -O2 -D_FORTIFY_SOURCE=2 -fno-strict-aliasing\ $(CWARNINGFLAGS) CFLAGS += \ @@ -146,7 +146,6 @@ -Wformat=2\ -Wmissing-declarations\ -Wmissing-prototypes\ - -Wstrict-aliasing=0\ -Wstrict-prototypes\ -Wswitch-default\ -Wpointer-arith\