ungccify parts of the build

configure.ac

@@ -10,6 +10,8 @@ target_alias=${target_alias-$host_alias}
 
 . ${srcdir}/configure.host
 
+AX_ENABLE_BUILDDIR
+
 AM_INIT_AUTOMAKE
 
 # The same as in boehm-gc and libstdc++. Have to borrow it from there.
@@ -34,6 +36,12 @@ AM_PROG_CC_C_O
 AC_PROG_LIBTOOL
 AC_CONFIG_MACRO_DIR([m4])
 
+AX_CFLAGS_WARN_ALL
+AX_CC_MAXOPT
+if test "x$GCC" = "xyes"; then
+  CFLAGS="$CFLAGS -fexceptions"
+fi
+
 AM_MAINTAINER_MODE
 
 AC_CHECK_HEADERS(sys/mman.h)