According to http://ftp.gnu.org/old-gnu/Manuals/glibc-2.2.3/html_chapter/libc_21.html
timelocal(2) is functionally identical to mktime(2), but more
mnemonically named. There is no timelocal(2) defined in musl libc.

--- a/snapper/AppUtil.cc	2015-02-18 18:54:03.000000000 +0100
+++ b/snapper/AppUtil.cc	2015-08-30 10:39:31.318158599 +0200
@@ -274,7 +274,7 @@
 	const char* p = strptime(str.c_str(), "%F %T", &s);
 	if (!p || *p != '\0')
 	    return (time_t)(-1);
-	return utc ? timegm(&s) : timelocal(&s);
+	return utc ? timegm(&s) : mktime(&s);
     }