so that when a glob has no expansion you don't get the glob back (
*.sh expands to empty rather than to "*.sh")

Produce CMake message when BugSplat is engaged so we can detect in build log.

Don't try to copy BugSplat DLLs when NOT engaged.

On TeamCity, set BUGSPLAT_DB from build-secrets.

Use the presence of $BUGSPLAT_DB, rather than a new CMake BUGSPLAT option, to
control whether CMake searches for BugSplat -- and passes LL_BUGSPLAT into C++.

When BUGSPLAT_DB is present, make viewer_manifest.py set "BugSplat DB" in
build_data.json, and "BugsplatServerURL" in Mac Info.plist.

Make llappviewerwin32.cpp read "BugSplat DB" from build_data.json.

Add placeholders for Mac hooks to suppress BugSplat prompt and send
SecondLife.log.

cmake -E copy does only one file at a time, and older CMake versions don't
handle wildcards. But cmake -E copy is specifically for portability. When the
copy operation itself is Darwin-only, we can count on having 'cp' available.

instead of the INSTALL_RPATH CMake property, which _should_ have worked.

The BugsplatMac framework is stamped with @rpath/BugsplatMac.framework/etc.,
so that's the dependency stamped into our viewer executable. To support that
lookup, direct CMake to add an appropriate RPATH to the executable.

The BugsplatMac package is built as a module requiring @import. Using @import
requires Objective-C++ module support, which requires the -fmodules switch.

BugSplat has no business introducing a new C++ API based on classic-C function
pointers without even a generic pass-through user data pointer!

Use WSTRINGIZE(), LL_TO_WSTRING(), wstringize() to produce required wide
strings. Use a lambda for callback that sends log file; use LLDir, if set, to
find the log file.

Introduce BUGSPLAT CMake variable to allow suppressing BugSplat.
Make BUGSPLAT CMake variable set LL_BUGSPLAT for C++ compilations.

Set viewer version macros on llappviewerwin32.cpp, llappviewerlinux.cpp and
llappdelegate-objc.mm -- because BugSplat needs the viewer version data, and
because the macOS BugSplat hook is engaged in an Objective-C++ function we
override in the app delegate.

Streamline convenience overload stringize(std::wstring); make convenience
overload wstringize(std::string) symmetrically convert from UTF-8 string.

Also eliminate STRINGIZE() et al. dependency on Boost.Phoenix: use lambdas
instead.

Using lambdas instead of template expansion necessitates reordering some code
in wrapllerrs.h.

Also use existing LL_TO_STRING() macro to stringize LL_VIEWER_CHANNEL in
llversioninfo.cpp and its tests.

No C++ source in llcommon references any of the BugSplat code.