Fix for asynchronous api (windows): Context iitialization didn't work, since client library doesn't use __WIN__ definition (instead we use _WIN32).

Author: holzboote@googlemail.com

include/my_context.h

@@ -25,7 +25,7 @@
   (This particular implementation uses Posix ucontext swapcontext().)
 */
 
-#ifdef __WIN__
+#ifdef _WIN32
 #define MY_CONTEXT_USE_WIN32_FIBERS 1
 #elif defined(__GNUC__) && __GNUC__ >= 3 && defined(__x86_64__) && !defined(__ILP32__)
 #define MY_CONTEXT_USE_X86_64_GCC_ASM