Fix botlib parser for negative int/float values, thanks to Makro for reporting (#4227).

code/botlib/be_ai_weight.c

@@ -64,13 +64,20 @@ int ReadValue(source_t *source, float *value)
 	if (!strcmp(token.string, "-"))
 	{
 		SourceWarning(source, "negative value set to zero\n");
-		if (!PC_ExpectTokenType(source, TT_NUMBER, 0, &token)) return qfalse;
-	} //end if
+
+		if(!PC_ExpectAnyToken(source, &token))
+		{
+			SourceError(source, "Missing return value\n");
+			return qfalse;
+		}
+	}
+
 	if (token.type != TT_NUMBER)
 	{
 		SourceError(source, "invalid return value %s\n", token.string);
 		return qfalse;
-	} //end if
+	}
+	
 	*value = token.floatvalue;
 	return qtrue;
 } //end of the function ReadValue