Not sure if this is wanted, but mesa likes to compile with '-std=c99
D_XOPEN_SOURCE=500', which leads to exciting crashes on x86_64 because
initstate() is not prototyped.

2013-11-13  Jon TURNEY  <jon.turney@dronecode.org.uk>

	* include/cygwin/stdlib.h(initstate, random, setstate, srandom) :
	Prototype if not __STRICT_ANSI__ or _XOPEN_SOURCE is defined appropriately.