Remove (Open)Watcom support.

This compiler is not being developed since several years and almost certainly
can't be used to build the current wxWidgets sources anyhow, so remove all
support for it, including a lot of extremely ugly workarounds for its bugs
with template functions.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76546 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/thread.h

@@ -513,8 +513,6 @@ public:
 
         // create a new thread and optionally set the stack size on
         // platforms that support that - call Run() to start it
-        // (special cased for watcom which won't accept 0 default)
-
     wxThreadError Create(unsigned int stackSize = 0);
 
         // starts execution of the thread - from the moment Run() is called
@@ -800,9 +798,7 @@ inline void wxMutexGuiLeave() { }
 
 // macros for entering/leaving critical sections which may be used without
 // having to take them inside "#if wxUSE_THREADS"
-// (the implementation uses dummy structs to force semicolon after the macro;
-// also notice that Watcom doesn't like declaring a struct as a member so we
-// need to actually define it in wxCRIT_SECT_DECLARE_MEMBER)
+// (the implementation uses dummy structs to force semicolon after the macro)
 #define wxENTER_CRIT_SECT(cs)            do {} while (0)
 #define wxLEAVE_CRIT_SECT(cs)            do {} while (0)
 #define wxCRIT_SECT_DECLARE(cs)          struct wxDummyCS##cs