diff --git a/src/mbyte.c b/src/mbyte.c
index 646235f..ccf23e8 100644
--- a/src/mbyte.c
+++ b/src/mbyte.c
@@ -5735,7 +5735,7 @@
 #endif
 
 #if defined(FEAT_GUI_X11) || defined(PROTO)
-# if defined(XtSpecificationRelease) && XtSpecificationRelease >= 6 && !defined(sun)
+# if defined(XtSpecificationRelease) && XtSpecificationRelease >= 6 && !defined(SUN_SYSTEM)
 #  define USE_X11R6_XIM
 # endif
 
diff --git a/src/os_unixx.h b/src/os_unixx.h
index 8ed52d1..f1aad2c 100644
--- a/src/os_unixx.h
+++ b/src/os_unixx.h
@@ -17,8 +17,8 @@
 # define signal sigset
 #endif
 
-   /* sun's sys/ioctl.h redefines symbols from termio world */
-#if defined(HAVE_SYS_IOCTL_H) && !defined(sun)
+   /* Sun's sys/ioctl.h redefines symbols from termio world */
+#if defined(HAVE_SYS_IOCTL_H) && !defined(SUN_SYSTEM)
 # include <sys/ioctl.h>
 #endif
 
diff --git a/src/pty.c b/src/pty.c
index c07256f..20ab65b 100644
--- a/src/pty.c
+++ b/src/pty.c
@@ -62,7 +62,7 @@
 #ifdef sinix
 #undef buf_T
 #endif
-# ifdef sun
+# ifdef SUN_SYSTEM
 #  include <sys/conf.h>
 # endif
 #endif
@@ -87,11 +87,11 @@
 # include <sys/ptem.h>
 #endif
 
-#if !defined(sun) && !defined(VMS) && !defined(MACOS)
+#if !defined(SUN_SYSTEM) && !defined(VMS) && !defined(MACOS)
 # include <sys/ioctl.h>
 #endif
 
-#if defined(sun) && defined(LOCKPTY) && !defined(TIOCEXCL)
+#if defined(SUN_SYSTEM) && defined(LOCKPTY) && !defined(TIOCEXCL)
 # include <sys/ttold.h>
 #endif
 
@@ -166,7 +166,7 @@
 # endif
     if (ioctl(fd, I_PUSH, "ldterm") != 0)
 	return -1;
-# ifdef sun
+# ifdef SUN_SYSTEM
     if (ioctl(fd, I_PUSH, "ttcompat") != 0)
 	return -1;
 # endif
@@ -391,7 +391,7 @@
 		continue;
 	    }
 #endif
-#if defined(sun) && defined(TIOCGPGRP) && !defined(SUNOS3)
+#if defined(SUN_SYSTEM) && defined(TIOCGPGRP) && !defined(SUNOS3)
 	    /* Hack to ensure that the slave side of the pty is
 	     * unused. May not work in anything other than SunOS4.1
 	     */
diff --git a/src/version.c b/src/version.c
index 0698606..536d218 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    123,
+/**/
     122,
 /**/
     121,
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