Merge branch 'jc/macos-homebrew-wo-reg-enhanced'

In case homebrew breaks REG_ENHANCED again, leave a in-code comment
to suggest use of our replacement regex as a workaround.

* jc/macos-homebrew-wo-reg-enhanced:
  regexp: leave a pointer to resurrect workaround for Homebrew

Author: gitster

compat/regcomp_enhanced.c

@@ -3,6 +3,11 @@
 
 int git_regcomp(regex_t *preg, const char *pattern, int cflags)
 {
+	/*
+	 * If you are on macOS with clang and fail to compile this line,
+	 * https://lore.kernel.org/git/458ad3c1-96df-4575-ee42-e6eb754f25f6@gmx.de/
+	 * might be relevant.
+	 */
 	if (!(cflags & REG_EXTENDED))
 		cflags |= REG_ENHANCED;
 	return regcomp(preg, pattern, cflags);