Define WEXITSTATUS macro for windows

Author: Thirumalai-Shaktivel

src/lpython/utils.cpp

@@ -24,6 +24,9 @@
     #if !defined S_ISDIR
         #define S_ISDIR(m) (((m) & _S_IFDIR) == _S_IFDIR)
     #endif
+
+    // For exit error code
+    #define WEXITSTATUS(status) (((status) >> 8) & 0x000000ff)
 #endif
 
 namespace LFortran {