Merge branch 'rs/compat-strdup' into maint

Code cleanup.

* rs/compat-strdup:
  compat: move strdup(3) replacement to its own file

git-compat-util.h

@@ -664,6 +664,14 @@ void *gitmemmem(const void *haystack, size_t haystacklen,
                 const void *needle, size_t needlelen);
 #endif
 
+#ifdef OVERRIDE_STRDUP
+#ifdef strdup
+#undef strdup
+#endif
+#define strdup gitstrdup
+char *gitstrdup(const char *s);
+#endif
+
 #ifdef NO_GETPAGESIZE
 #define getpagesize() sysconf(_SC_PAGESIZE)
 #endif