pg_escape_* functions were not available on win32 due to a missing define

#if this breaks the build because the win32 pg libs don't export the functions
#we should consider implementing them somehow else
#some linuxtag work

main/config.w32.h.in

@@ -164,3 +164,4 @@
 #define SIZEOF_INT 4
 #define HAVE_GLOB
 #define PHP_SHLIB_SUFFIX "dll"
+#define HAVE_PQESCAPE