1 files changed, 21 insertions, 0 deletions
diff --git a/build/m4/ax_c_lto.m4 b/build/m4/ax_c_lto.m4
new file mode 100644
index 0000000..7e6bc01
--- /dev/null
+++ b/build/m4/ax_c_lto.m4
@@ -0,0 +1,21 @@
+# AC_C_LTO
+# -------------
+# Define HAVE_LTO if -flto works.
+AN_IDENTIFIER([lto], [AC_C_LTO])
+AC_DEFUN([AC_C_LTO],
+[AC_CACHE_CHECK([if -flto builds executables], ac_cv_c_lto,
+[AC_RUN_IFELSE(
+   [AC_LANG_SOURCE(
+      [[#include <stdio.h>
+        int main(int argc, char **argv) {
+          return 0;
+        }
+      ]])],
+   [ac_cv_c_lto=yes],
+   [ac_cv_c_lto=no],
+   [ac_cv_c_lto=${ac_cv_c_lto_cross_compile}])])
+if test "${ac_cv_c_lto}" = "yes"; then
+  AC_DEFINE([HAVE_LTO], 1,
+           [Define to 1 if -flto works.])
+fi
+])# AC_C_LTO