Revert "Allow adding extra CFLAGS with a configure option."

This reverts commit 64b3cef.

Apparently, setting CFLAGS won't override the preset AM_CFLAGS
afterall. Not sure why this was giving me a problem before.

Makefile.am

@@ -25,8 +25,7 @@ COMMON_CFLAGS=-Wall -Wformat -Wformat-security
 # The next line is commented out by default in shipping libarchive releases.
 # It is uncommented by default in trunk.
 DEV_CFLAGS=-Werror -Wextra -Wunused -Wshadow -Wmissing-prototypes -Wcast-qual
-EXTRA_CFLAGS = @EXTRA_CFLAGS@
-AM_CFLAGS=$(COMMON_CFLAGS) $(DEV_CFLAGS) $(EXTRA_CFLAGS)
+AM_CFLAGS=$(COMMON_CFLAGS) $(DEV_CFLAGS)
 PLATFORMCPPFLAGS = @PLATFORMCPPFLAGS@
 AM_CPPFLAGS=$(PLATFORMCPPFLAGS)
 

configure.ac

@@ -190,12 +190,6 @@ esac
 AM_CONDITIONAL([BUILD_BSDCPIO], [ test "$build_bsdcpio" = yes ])
 AM_CONDITIONAL([STATIC_BSDCPIO], [ test "$static_bsdcpio" = yes ])
 
-AC_ARG_WITH([extra-cflags],
-  [AS_HELP_STRING([--with-extra-cflags=CFLAGS], [use extra CFLAGS])],
-  [], [enable_extra_cflags= ])
-
-EXTRA_CFLAGS=$with_extra_cflags
-
 # Set up defines needed before including any headers
 case $host in
   *mingw* | *cygwin* )
@@ -791,5 +785,4 @@ case "$host_os" in
 	;;
 esac
 
-AC_SUBST(EXTRA_CFLAGS)
 AC_OUTPUT