diff --git a/src/vim.h b/src/vim.h
index de26c63..ef75ea2 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -268,6 +268,11 @@
 # define UNUSED
 #endif
 
+/* Used to check for "sun", "__sun" is used by newer compilers. */
+#if defined(__sun)
+# define SUN_SYSTEM
+#endif
+
 /* if we're compiling in C++ (currently only KVim), the system
  * headers must have the correct prototypes or nothing will build.
  * conversely, our prototypes might clash due to throw() specifiers and
@@ -2487,7 +2492,7 @@
 #define FNE_INCL_BR	1	/* include [] in name */
 #define FNE_CHECK_START	2	/* check name starts with valid character */
 
-#if (defined(sun) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)) \
+#if (defined(SUN_SYSTEM) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)) \
 	&& defined(S_ISCHR)
 # define OPEN_CHR_FILES
 #endif