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

src/msw/thread.cpp

@@ -60,8 +60,7 @@
 // which should be used instead of Win32 ::CreateThread() if possible
 #if defined(__VISUALC__) || \
     (defined(__BORLANDC__) && (__BORLANDC__ >= 0x500)) || \
-    (defined(__GNUG__) && defined(__MSVCRT__)) || \
-    defined(__WATCOMC__)
+    (defined(__GNUG__) && defined(__MSVCRT__))
 
 #ifndef __WXWINCE__
     #undef wxUSE_BEGIN_THREAD
@@ -646,14 +645,6 @@ bool wxThreadInternal::Create(wxThread *thread, unsigned int stackSize)
     // creation instead of Win32 API one because otherwise we will have memory
     // leaks if the thread uses C RTL (and most threads do)
 #ifdef wxUSE_BEGIN_THREAD
-
-    // Watcom is reported to not like 0 stack size (which means "use default"
-    // for the other compilers and is also the default value for stackSize)
-#ifdef __WATCOMC__
-    if ( !stackSize )
-        stackSize = 10240;
-#endif // __WATCOMC__
-
     m_hThread = (HANDLE)_beginthreadex
                         (
                           NULL,                             // default security