patch 8.1.0380: "make proto" doesn't work well

Problem:    "make proto" doesn't work well.
Solution:   Define a few more types for cproto.  Update proto files.  Fix that
            workshop didn't build.
diff --git a/src/vim.h b/src/vim.h
index 6d1c312..c30e8db 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -9,10 +9,7 @@
 #ifndef VIM__H
 # define VIM__H
 
-#ifdef PROTO
-/* cproto runs into trouble when this type is missing */
-typedef double _Float128;
-#endif
+#include "protodef.h"
 
 /* use fastcall for Borland, when compiling for Win32 */
 #if defined(__BORLANDC__) && defined(WIN32) && !defined(DEBUG)