Cosmetic fixes (NFC)

- Fix includes order
- Add  comments after endifs to indicate what they end

Author: danra

stdlib/public/Platform/Misc.c

@@ -10,10 +10,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <fcntl.h>
 #include <semaphore.h>
+#include <sys/types.h>
+#include <sys/stat.h>
 
 extern int
 _swift_Platform_open(const char *path, int oflag, mode_t mode) {
@@ -62,12 +62,12 @@ extern long double
 _swift_Darwin_lgammal_r(long double x, int *psigngam) {
   return lgammal_r(x, psigngam);
 }
-#endif
+#endif // defined(__APPLE__)
 
 #if defined(__FreeBSD__)
 extern char **
 _swift_FreeBSD_getEnv() {
   extern char **environ;
   return environ;
 }
-#endif
+#endif // defined(__FreeBSD__)