macOS: define OS version macro if missing

Author: rscharfe

git-compat-util.h

@@ -1010,6 +1010,11 @@ void bug_fl(const char *file, int line, const char *fmt, ...);
 #endif
 #endif
 
+#ifdef __APPLE__
+#ifndef __ENVIRONMENT_OS_VERSION_MIN_REQUIRED__
+#define __ENVIRONMENT_OS_VERSION_MIN_REQUIRED__ 140000
+#endif
+
 #ifndef SHELL_PATH
 # define SHELL_PATH "/bin/sh"
 #endif