patch 8.1.2366: using old C style comments

Problem:    Using old C style comments.
Solution:   Use // comments where appropriate.
diff --git a/src/os_beos.h b/src/os_beos.h
index 0aa6f99..caf3952 100644
--- a/src/os_beos.h
+++ b/src/os_beos.h
@@ -20,8 +20,8 @@
 #undef	BEOS_DR8
 #define	BEOS_PR_OR_BETTER
 
-/* select emulation */
+// select emulation
 
 #ifndef PROTO
-# include <net/socket.h>		/* for typedefs and #defines only */
+# include <net/socket.h>		// for typedefs and #defines only
 #endif