build: enable LTO and _FORTIFY_SOURCE with optimization

If building with optimization enabled, enable LTO.

diff --git a/configure.ac b/configure.ac
index 648ff12..e7bab61 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -226,8 +226,18 @@ CC_CHECK_FLAGS_APPEND(with_cflags, [CFLAGS], [\
                       -fvisibility=hidden \
                       -ffunction-sections \
                       -fdata-sections])
-AC_SUBST([OUR_CFLAGS], "$with_cflags $with_coverage_cflags")
 
+AS_CASE([$CFLAGS], [*-O[[12345\ ]]*],
+       [CC_CHECK_FLAGS_APPEND([with_cflags], [CFLAGS], [\
+        -flto -ffat-lto-objects])],
+       [AC_MSG_RESULT([skipping -flto, optimization not enabled])])
+
+AS_CASE([$CFLAGS], [*-O[[12345\ ]]*],
+        [CC_CHECK_FLAGS_APPEND([with_cppflags], [CPPFLAGS], [\
+               -Wp,-D_FORTIFY_SOURCE=2])],
+        [AC_MSG_RESULT([skipping -D_FORTIFY_SOURCE, optimization not enabled])])
+
+AC_SUBST([OUR_CFLAGS], "$with_cflags $with_coverage_cflags")
 
 CC_CHECK_FLAGS_APPEND([with_ldflags], [LDFLAGS], [ \
                       -Wl,--as-needed \