+# ------------------------------------------------------------------------------
+# On some distributions -flto, even if available, leads to linking errors.
+# We therefore make it optional
+have_lto=no
+AC_ARG_ENABLE([lto],
+ [AS_HELP_STRING([--disable-lto], [Disable link time optimization (default: test)])])
+
+AS_IF([test "x$enable_lto" != "xno"], [
+ AS_CASE([$CFLAGS], [*-O[[12345sz\ ]]*],
+ [have_lto=yes],
+ [AC_MSG_RESULT([skipping -flto, optimization not enabled])])
+ AS_IF([test "$have_lto" != "no"],
+ [CC_CHECK_FLAGS_APPEND([with_cflags], [CFLAGS], [-flto])]
+ )
+ AC_SUBST([OUR_CFLAGS], "$with_cflags $sanitizer_cflags")
+])
+
+# ------------------------------------------------------------------------------