diff --git a/configure.ac b/configure.ac
index db81e4a64..4eff41aa0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3,7 +3,7 @@
 # Process this file with autoconf to produce a configure script.
 
 AC_PREREQ([2.63])
-AC_INIT([leech], [0.1.17], [https://github.com/larsewi/leech/issues], [leech],
+AC_INIT([leech], [0.1.18], [https://github.com/larsewi/leech/issues], [leech],
         [https://github.com/larsewi/leech])
 AC_CONFIG_SRCDIR([lib/leech.h])
 
diff --git a/lib/leech.c b/lib/leech.c
index a29915dd7..238b46358 100644
--- a/lib/leech.c
+++ b/lib/leech.c
@@ -127,7 +127,7 @@ static bool Purge(const LCH_Instance *const instance) {
 
     bool is_block_id = true;
     for (const char *ch = filename; *ch != '\0'; ch++) {
-      if (isxdigit(*ch) == 0) {
+      if (isxdigit((int)(*ch)) == 0) {
         is_block_id = false;
         break;
       }
diff --git a/lib/string_lib.h b/lib/string_lib.h
index f9b3f6a40..c5d644a38 100644
--- a/lib/string_lib.h
+++ b/lib/string_lib.h
@@ -40,4 +40,4 @@ bool LCH_StringParseNumber(const char *str, long *number);
 bool LCH_StringParseVersion(const char *str, size_t *major, size_t *minor,
                             size_t *patch);
 
-#endif  // _LEECH_STRING_LIB_H
\ No newline at end of file
+#endif  // _LEECH_STRING_LIB_H