Compile fix for MSVC: Do not include sys/resources.h

Do not include header files when compiling with MSVC that do not
exist and which are also not included when compiling with MINGW.
A direct consequence is that git can be compiled again with MSVC
because the missing "sys/resources.h" is no longer included.

Instead of current

	#ifndef mingw32 is the only one that is strange
        ... everything for systems that is not strange ...
        #else
        ... include mingw specific tweaks ...
        #endif
        #ifdef msvc is also strange
        ... include msvc specific tweaks ...
        #endif

it turns things around and says what it wants to achieve in a more direct
way, i.e.

	#if mingw32
        #include "compat/mingw.h"
	#elif msvc
        #include "compat/msvc.h"
	#else
        ... all the others ...
	#endif

which makes it a lot simpler.

Signed-off-by: Vincent van Ravesteijn <vfr@lyx.org>
Helped-by: Junio C Hamano <gitster@pobox.com>
Acked-by: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-compat-util.h

@@ -116,7 +116,12 @@
 #else
 #include <poll.h>
 #endif
-#ifndef __MINGW32__
+#if defined(__MINGW32__)
+/* pull in Windows compatibility stuff */
+#include "compat/mingw.h"
+#elif defined(_MSC_VER)
+#include "compat/msvc.h"
+#else
 #include <sys/wait.h>
 #include <sys/resource.h>
 #include <sys/socket.h>
@@ -145,12 +150,6 @@
 #include <grp.h>
 #define _ALL_SOURCE 1
 #endif
-#else 	/* __MINGW32__ */
-/* pull in Windows compatibility stuff */
-#include "compat/mingw.h"
-#endif	/* __MINGW32__ */
-#ifdef _MSC_VER
-#include "compat/msvc.h"
 #endif
 
 #ifndef NO_LIBGEN_H