patch 7.4.1895
Problem: Cannot use a window ID where a window number is expected.
Solution: Add LOWEST_WIN_ID, so that the window ID can be used where a
number is expected.
diff --git a/src/vim.h b/src/vim.h
index fb991dc..d573cea 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -2334,4 +2334,7 @@
#define DIP_OPT 0x10 /* also use "opt" directory in 'packpath' */
#define DIP_NORTP 0x20 /* do not use 'runtimepath' */
+/* Lowest number used for window ID. Cannot have this many windows. */
+#define LOWEST_WIN_ID 1000
+
#endif /* VIM__H */