[MINOR] standard: change arg type from const char* to char*

inetaddr_host_lim_ret() used to make use of const char** for some
args, but that make it impossible ot use char** due to the way
controls are made by gcc. So let's change that.
diff --git a/include/common/standard.h b/include/common/standard.h
index 71c5b76..bdb6ec0 100644
--- a/include/common/standard.h
+++ b/include/common/standard.h
@@ -303,7 +303,7 @@
 extern unsigned int read_uint(const char **s, const char *end);
 unsigned int inetaddr_host(const char *text);
 unsigned int inetaddr_host_lim(const char *text, const char *stop);
-unsigned int inetaddr_host_lim_ret(const char *text, char *stop, const char **ret);
+unsigned int inetaddr_host_lim_ret(char *text, char *stop, char **ret);
 
 static inline char *cut_crlf(char *s) {