patch 7.4.1008
Problem: The OS/2 code pollutes the source while nobody uses it these days.
Solution: Drop the support for OS/2.
diff --git a/src/macros.h b/src/macros.h
index caaca9a..737eddf 100644
--- a/src/macros.h
+++ b/src/macros.h
@@ -231,7 +231,7 @@
#if defined(UNIX) || defined(VMS) /* open in rw------- mode */
# define mch_open_rw(n, f) mch_open((n), (f), (mode_t)0600)
#else
-# if defined(MSDOS) || defined(MSWIN) || defined(OS2) /* open read/write */
+# if defined(MSDOS) || defined(MSWIN) /* open read/write */
# define mch_open_rw(n, f) mch_open((n), (f), S_IREAD | S_IWRITE)
# else
# define mch_open_rw(n, f) mch_open((n), (f), 0)