Don't define S_IRGRP in AndroidConfig.h.

Nothing seems to be relying on this anyway.

Change-Id: I24e2509e4d24bc445961430bb74f8ca04135bc37
diff --git a/core/combo/include/arch/windows/AndroidConfig.h b/core/combo/include/arch/windows/AndroidConfig.h
index fbda250..b4abdca 100644
--- a/core/combo/include/arch/windows/AndroidConfig.h
+++ b/core/combo/include/arch/windows/AndroidConfig.h
@@ -76,11 +76,4 @@
 #define _WIN32 1
 #define _WIN32_WINNT 0x0500     /* admit to using >= Win2K */
 
-/*
- * Various definitions missing in MinGW
- */
-#ifdef USE_MINGW
-#define S_IRGRP 0
-#endif
-
 #endif /*_ANDROID_CONFIG_H*/