Xerces-C currently supports POSIX and Win32 threading models with dedicated mutex manager classes. C++ standards since C++11 support native mutexes which will work on any supported platform.
The attached patch adds a StdMutexMgr class and the necessary Autoconf and CMake logic to check if C++ mutexes are available. If not, it will fall back to the existing managers.
On all but the most current compilers, it will continue to use POSIX/Win32 managers. On the most recent compilers, which default to C++14, the standard mutexes will be used. On older compilers, the user must explicitly enable by setting CXXFLAGS=-std=c++11 or later.
for build and test results. You'll see that GCC on Linux is using POSIX mutex, while clang on MacOS X is using standard mutex. On Windows, Cygwin uses POSIX mutex while MinGW and MSVC uses standard mutex.