Fix [9e31fd944934e269121fa78ff56b7b86f33e6db6|9e31fd9449]: X11/X.h and Windows.h have conflicting symbols.

*** POTENTIAL INCOMPATIBILITY *** on Windows only: gcc/clang/MSVC will generate new warnings in extensions when the "None" symbol is used incorrectly.
Those warnings are all fixed in the core, that's what most of this commit is doing.

2 files changed, 16 insertions, 7 deletions

diff --git a/xlib/X11/X.h b/xlib/X11/X.h
index daf2283..b43967e 100644
--- a/xlib/X11/X.h
+++ b/xlib/X11/X.h
@@ -73,7 +73,9 @@ typedef unsigned long KeyCode;	/* In order to use IME, the Macintosh needs
  * RESERVED RESOURCE AND CONSTANT DEFINITIONS
  *****************************************************************/
 
-#define None                 0L	/* universal null resource or null atom */
+#ifndef _WIN32
+#   define None              0L      /* See bug [9e31fd9449] and below */
+#endif
 
 #define ParentRelative       1L	/* background pixmap in CreateWindow
 				    and ChangeWindowAttributes */
@@ -179,13 +181,20 @@ are reserved in the protocol for errors and replies. */
 
 #define ShiftMask		(1<<0)
 #define LockMask		(1<<1)
-#define ControlMask		(1<<2)
+#ifndef _WIN32
+#   define ControlMask		(1<<2) /* See bug [9e31fd9449] and below */
+#endif
 #define Mod1Mask		(1<<3)
 #define Mod2Mask		(1<<4)
 #define Mod3Mask		(1<<5)
 #define Mod4Mask		(1<<6)
 #define Mod5Mask		(1<<7)
 
+/* See bug [9e31fd9449], this way prevents conflicts with Win32 headers */
+#ifdef _WIN32
+enum _Bug9e31fd9449 { None = 0, ControlMask = (1<<2) };
+#endif
+
 /* modifier names.  Used to build a SetModifierMapping request or
    to read a GetModifierMapping request.  These correspond to the
    masks defined above. */
diff --git a/xlib/xgc.c b/xlib/xgc.c
index b18cb9e..38d2783 100644
--- a/xlib/xgc.c
+++ b/xlib/xgc.c
@@ -50,7 +50,7 @@
 static TkpClipMask *AllocClipMask(GC gc) {
     TkpClipMask *clip_mask = (TkpClipMask*) gc->clip_mask;
 
-    if (clip_mask == None) {
+    if (clip_mask == NULL) {
 	clip_mask = (TkpClipMask*) ckalloc(sizeof(TkpClipMask));
 	gc->clip_mask = (Pixmap) clip_mask;
 #ifdef MAC_OSX_TK
@@ -126,7 +126,7 @@ XCreateGC(
     gp = (XGCValues *) ckalloc(sizeof(XGCValues) + MAX_DASH_LIST_SIZE +
 	    gcCacheSize);
     if (!gp) {
-	return None;
+	return NULL;
     }
 
 #define InitField(name,maskbit,default) \
@@ -269,7 +269,7 @@ int XFreeGC(
     Display *d,
     GC gc)
 {
-    if (gc != None) {
+    if (gc != NULL) {
 	FreeClipMask(gc);
 	TkpFreeGCCache(gc);
 	ckfree((char *) gc);
@@ -465,8 +465,8 @@ TkSetRegion(
     GC gc,
     TkRegion r)
 {
-    if (r == None) {
-	Tcl_Panic("must not pass None to TkSetRegion for compatibility with X11; use XSetClipMask instead");
+    if (r == NULL) {
+	Tcl_Panic("must not pass NULL to TkSetRegion for compatibility with X11; use XSetClipMask instead");
     } else {
 	TkpClipMask *clip_mask = AllocClipMask(gc);