just use ctype

IRooc · IRooc · commit 72dd22e52527 · 2023-02-18T18:39:05.000+01:00
diff --git a/src/common.h b/src/common.h
@@ -7,7 +7,7 @@
 #include "./la.h"
 
 #ifdef _WIN32
-   int isalnum(int c);
+#     include <ctype.h>
 #endif // _WIN32
 
 #define SCREEN_WIDTH 800
