Add ax_gcc_builtin.m4 for checking GCC built-in functions
@@ -1197,10 +1197,11 @@ Some parts of converters/loader.c are imported from @uobikiemukot's
### ax_gcc_var_attribute / ax_gcc_func_attribute
-These are useful m4 macros for detecting some GCC attributes.
+These are useful m4 macros for detecting some GCC attributes / built-in functions.
http://www.gnu.org/software/autoconf-archive/ax_gcc_var_attribute.html
http://www.gnu.org/software/autoconf-archive/ax_gcc_func_attribute.html
+http://www.gnu.org/software/autoconf-archive/ax_gcc_builtin.html
> Copyright (c) 2013 Gabriele Svelto <gabriele.svelto@gmail.com>
>
