diff --git a/Makefile b/Makefile
index e107202..54f0d19 100644
--- a/Makefile
+++ b/Makefile
@@ -39,7 +39,7 @@ $(DYLIBNAME): $(OBJ)
 		$(DYLIBCMD) $< $(LDFLAGS)
 	
 $(STLIBNAME): $(OBJ)
-		ar rcs $@ $<
+		$(AR) rcs $@ $<
 
 $(OBJ): cJSON.c cJSON.h 
 
diff --git a/cJSON.c b/cJSON.c
index 1fc2e39..f6d48a5 100644
--- a/cJSON.c
+++ b/cJSON.c
@@ -50,7 +50,7 @@ static int cJSON_strcasecmp(const char *s1, const char *s2)
     {
         return 1;
     }
-    for(; tolower(*s1) == tolower(*s2); ++s1, ++s2)
+    for(; tolower(*(const unsigned char *)s1) == tolower(*(const unsigned char *)s2); ++s1, ++s2)
     {
         if (*s1 == 0)
         {