Update the po files with the transifex client and do a msgmerge.
Replace cmake/FindGettext.cmake with the current version, and fix a bug
in it that would not allow files with multiple periods such as
zh_TW.Big5.po. Also disable msgmerge in GETTEXT_CREATE_TRANSLATIONS
otherwise it would create too many very spammy commits.
Replace language list in po/wxvbam/CMakeLists.txt (where the .pot and
.po files are) with a list made with file(GLOB ...), so that all the new
languages are pulled in.
When determining gcc/clang flags, save resulting C flags as MY_C_FLAGS,
C++ flags as MY_CXX_FLAGS, and linker flags as MY_C_LINKER_FLAGS, then
use them in the Wx OpenGL compile test.
This fixes the test erroneously failing on git mxe on mac.
Also, don't use -fPIC on Win32, set Wx defines separately from the test,
and save all CMAKE_REQUIRED_* variables before the test and restore them
afterwards.
Rafael Kitover