+ AC_MSG_CHECKING(if $CC accepts -fno-builtin-memset)
+ saved_CFLAGS="$CFLAGS"
+ CFLAGS="$CFLAGS -fno-builtin-memset"
+ AC_LINK_IFELSE( [AC_LANG_SOURCE([[
+#include <string.h>
+int main(void){char b[10]; memset(b, 0, sizeof(b));}
+ ]])],
+ [ AC_MSG_RESULT(yes) ],
+ [ AC_MSG_RESULT(no)
+ CFLAGS="$saved_CFLAGS" ]
+)
+
+ # -fstack-protector-all doesn't always work for some GCC versions
+ # and/or platforms, so we test if we can. If it's not supported
+ # on a given platform gcc will emit a warning so we use -Werror.
+ if test "x$use_stack_protector" = "x1"; then
+ for t in -fstack-protector-all -fstack-protector; do
+ AC_MSG_CHECKING(if $CC supports $t)
+ saved_CFLAGS="$CFLAGS"
+ saved_LDFLAGS="$LDFLAGS"
+ CFLAGS="$CFLAGS $t -Werror"
+ LDFLAGS="$LDFLAGS $t -Werror"
+ AC_LINK_IFELSE(
+ [AC_LANG_SOURCE([
+#include <stdio.h>
+int main(void){char x[[256]]; snprintf(x, sizeof(x), "XXX"); return 0;}
+ ])],
+ [ AC_MSG_RESULT(yes)
+ CFLAGS="$saved_CFLAGS $t"
+ LDFLAGS="$saved_LDFLAGS $t"
+ AC_MSG_CHECKING(if $t works)
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([
+#include <stdio.h>
+int main(void){char x[[256]]; snprintf(x, sizeof(x), "XXX"); return 0;}
+ ])],
+ [ AC_MSG_RESULT(yes)
+ break ],
+ [ AC_MSG_RESULT(no) ],
+ [ AC_MSG_WARN([cross compiling: cannot test])
+ break ]
+ )
+ ],
+ [ AC_MSG_RESULT(no) ]
+ )
+ CFLAGS="$saved_CFLAGS"
+ LDFLAGS="$saved_LDFLAGS"
+ done
+ fi
+