Fix mingw includes

Author: kuba160

os/generic_win_base.h

@@ -24,10 +24,10 @@
 // Unices provide `howmany` via sys/param.h
 #define howmany(x, y)  (((x) + ((y) - 1)) / (y))
 
-#ifndef HAVE_MODE_T
+#ifndef __MINGW64__
 typedef int mode_t;
-#endif
 typedef void pthread_attr_t;
+#endif
 
 #ifndef API_AVAILABLE
 #define API_AVAILABLE(...)

src/shims/generic_win_stubs.h

@@ -25,9 +25,11 @@ typedef __typeof__(_Generic((__SIZE_TYPE__)0,                                  \
 			    unsigned short : (short)0,                         \
 			    unsigned char : (signed char)0)) ssize_t;
 
+#ifndef __MINGW64__
 #define S_ISDIR(mode)  (((mode) & S_IFMT) == S_IFDIR)
 #define S_ISFIFO(mode) ((mode) & _S_IFIFO)
 #define S_ISREG(mode)  ((mode) & _S_IFREG)
+#endif
 #define S_ISSOCK(mode) 0
 
 #define O_NONBLOCK 04000