Bug 1359908 Add FORTIFY_SOURCE to gcc and clang builds by default r=froydnj

This adds a section in both old-configure.in's for hardening flags.

In old-configure.in we add $HARDENING_CFLAGS (which are turned on by
--enable-hardening) and are defined in toolchain.configure (and
which does compiler detection there.) We then add non-optional
hardening flags, performing compiler detection here.

In js/src/old-configure.in we follow the same pattern, but omit
$HARDENING_CFLAGS because we don't apply the current lone flag
to js (doing so is Bug 1359905).

MozReview-Commit-ID: EFE0Pc7yZHa

--HG--
extra : rebase_source : f793e665cabe3d33bdc73fc8a68208d69b55137a

js/src/old-configure.in

@@ -543,6 +543,15 @@ esac
 
 MOZ_DOING_LTO(lto_is_enabled)
 
+dnl ========================================================
+dnl Add optional and non-optional hardening flags
+dnl ========================================================
+if test "$GNU_CC" -o test -n "${CLANG_CC}${CLANG_CL}"; then
+   CFLAGS="$CFLAGS -D_FORTIFY_SOURCE=2"
+   CPPFLAGS="$CPPFLAGS -D_FORTIFY_SOURCE=2"
+   CXXFLAGS="$CXXFLAGS -D_FORTIFY_SOURCE=2"
+fi
+
 dnl ========================================================
 dnl System overrides of the defaults for target
 dnl ========================================================

old-configure.in

@@ -493,11 +493,19 @@ if test -n "$COMPILE_ENVIRONMENT"; then
    MOZ_CONFIG_SANITIZE
 fi
 
-# Add the hardening flags from moz.configure
+dnl ========================================================
+dnl Add optional and non-optional hardening flags
+dnl ========================================================
 CFLAGS="$CFLAGS $HARDENING_CFLAGS"
 CPPFLAGS="$CPPFLAGS $HARDENING_CFLAGS"
 CXXFLAGS="$CXXFLAGS $HARDENING_CFLAGS"
 
+if test "$GNU_CC" -o test -n "${CLANG_CC}${CLANG_CL}"; then
+   CFLAGS="$CFLAGS -D_FORTIFY_SOURCE=2"
+   CPPFLAGS="$CPPFLAGS -D_FORTIFY_SOURCE=2"
+   CXXFLAGS="$CXXFLAGS -D_FORTIFY_SOURCE=2"
+fi
+
 dnl ========================================================
 dnl GNU specific defaults
 dnl ========================================================