--- ./exp_strf.c	2000-01-06 23:22:05.000000000 +0000
+++ ../exp_strf.c	2018-03-22 19:58:34.428090961 +0000
@@ -99,7 +99,7 @@
 #else
 
 #ifndef strchr
-extern char *strchr(const char *str, int ch);
+extern char __attribute__((overloadable)) *strchr(const char *str, int ch);
 #endif
 
 extern char *getenv(const char *v);