Fix coverity reports (#304621, #304620)

Comparisons against MAX_SAFE_INT were done in the int domain, rather than
the source domain.

Author: H1GHGuY

core/semver.c

@@ -49,7 +49,7 @@ strcut (char *str, int begin, int len) {
   size_t l;
   l = strlen(str);
 
-  if((int)l < 0 || (int)l > MAX_SAFE_INT) return -1;
+  if(l > (size_t)MAX_SAFE_INT) return -1;
 
   if (len < 0) len = l - begin + 1;
   if (begin + len > (int)l) len = l - begin;
@@ -88,14 +88,17 @@ binary_comparison (int x, int y) {
 
 static int
 parse_int (const char *s) {
-  int valid, num;
+  int valid;
+  long int num;
   valid = has_valid_chars(s, NUMBERS);
   if (valid == 0) return -1;
 
   num = strtol(s, NULL, 10);
   if (num > MAX_SAFE_INT) return -1;
+  /* Shouldn't happen because '-' is a delimiter! */
+  if (num < 0) return -1;
 
-  return num;
+  return (int)num;
 }
 
 /*