diff --git a/git-compat-util.h b/git-compat-util.h
index 92d79673f8..ede9408bbd 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -183,7 +183,13 @@ void *gitmemmem(const void *haystack, size_t haystacklen,
                 const void *needle, size_t needlelen);
 #endif
 
-#if !defined(__GLIBC_PREREQ) && !__GLIBC_PREREQ(2, 1)
+#ifdef __GLIBC_PREREQ
+#if __GLIBC_PREREQ(2, 1)
+#define HAVE_STRCHRNUL
+#endif
+#endif
+
+#ifndef HAVE_STRCHRNUL
 #define strchrnul gitstrchrnul
 static inline char *gitstrchrnul(const char *s, int c)
 {