Reverts "Build polygon clipper only in tools builds" (see #17319)
which allows to build Clipper with tools disabled (release) and because
of that, Clipper has to be patched to optionally disable exceptions in
order to be built on some platforms.
Patched Clipper 6.4.2 to be compiled with exceptions enabled/disabled.
and ensure that Clipper-specific exception macros are defined: don't use
exceptions by default unless exception handling is detected.
Compilation with exceptions will be determined by various
C++ exceptions defines:
* ` __cpp_exceptions` is part of C++ feature testing macros (since C++98);
* `__EXCEPTIONS` is used by some GNU compilers;
* `_CPPUNWIND` is used by MSVC.
The user can override specific exceptions behavior via corresponding
`*_USER` macros (i.e. compiling for embedded systems).
Andrii Doroshenko (Xrayez)
Rémi Verschelde
Juan Linietsky