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

docs/doxygen/mainpages/devtips.h

@@ -44,7 +44,7 @@ The file @c "wx/wxprec.h" includes @c "wx/wx.h". Although this incantation may
 seem quirky, it is in fact the end result of a lot of experimentation, and
 several Windows compilers to use precompilation which is largely automatic for
 compilers with necessary support. Currently it is used for Visual C++
-(including embedded Visual C++), Borland C++, Open Watcom C++, Digital Mars C++
+(including embedded Visual C++), Borland C++, Digital Mars C++
 and newer versions of GCC. Some compilers might need extra work from the
 application developer to set the build environment up as necessary for the
 support.
@@ -111,9 +111,9 @@ and this must not be changed.
 On Microsoft Windows, wxWidgets has a different set of makefiles for each
 compiler, because each compiler's @c 'make' tool is slightly different. Popular
 Windows compilers that we cater for, and the corresponding makefile extensions,
-include: Microsoft Visual C++ (.vc), Borland C++ (.bcc), OpenWatcom C++ (.wat)
-and MinGW/Cygwin (.gcc). Makefiles are provided for the wxWidgets library
-itself, samples, demos, and utilities.
+include: Microsoft Visual C++ (.vc), Borland C++ (.bcc) and MinGW/Cygwin
+(.gcc). Makefiles are provided for the wxWidgets library itself, samples,
+demos, and utilities.
 
 On Linux, Mac and OS/2, you use the @c 'configure' command to generate the
 necessary makefiles. You should also use this method when building with