build: detect availability of -z now, relro and noexecstack linker op…

…tions

Signed-off-by: Tomasz Kantecki <[email protected]>

configure.ac

@@ -79,6 +79,21 @@ AS_IF([test "x$intel_cet_enabled" = "xyes"], [
         AC_DEFINE(INTEL_CET_ENABLED, [1], [Intel CET enabled.])
 ])
 
+# check if LD -z options are supported
+LDFLAGS="\
+-Wl,-z,noexecstack \
+-Wl,-z,relro \
+-Wl,-z,now \
+"
+AC_MSG_CHECKING([if $LD supports $LDFLAGS])
+AC_LINK_IFELSE([AC_LANG_PROGRAM([[]], [[
+int main(int argc, char **argv)
+{
+	return 0;
+}]])],
+	[AC_MSG_RESULT([yes])],
+	[AC_MSG_RESULT([no]) LDFLAGS=""]
+)
 
   # Pick an assembler yasm or nasm
   if test x"$AS" = x""; then
@@ -290,13 +305,6 @@ my_CFLAGS="\
 "
 AC_SUBST([my_CFLAGS])
 
-AM_LDFLAGS="\
--Wl,-z,noexecstack \
--Wl,-z,relro \
--Wl,-z,now \
-"
-AC_SUBST([AM_LDFLAGS])
-
 AC_CONFIG_FILES([\
 	Makefile\
 	libisal.pc