Reading it again strdiff is the same as strspn, but your's doesn't actually handle c strings and reads past null. You can do feature tests yourself without pulling in the whole autotools mess: http://git.musl-libc.org/cgit/musl/tree/configure

Thanks! that helps!

Is it still possible to build using cmake?

I too reliably avoid libraries that depend on these old bloated tools (although I appreciate its helpful for packaging; the script complexity and lack of portability is undeniably a trade off cost in using automake; the usefulness of this library for me would be for a static embedded use case, where automake is of questionable value)

well. implementing these feature testing scripts is kinda waste of time. so I rather to pick up autotools, which provides a integrated features.

to use it for a static embedded use case, you may write your own build script to compile the library (it's not hard to write one). the cflags are describe in src/Makefile.am

and you can use pkg-config to list the flags you need.

One thing you might want to consider (or might not) is looking at Mongrel 2. It uses ANSI C and supports a variety of platforms, using only gmake and standard macros. I haven't looked at the code very much myself, but it's a pretty neat accomplishments.