[MinGW-dvlpr] Implementation of __gthr_win32_mutex_... APIs

[Wu Y. <ad...@ne...>]

In order to write some cross-platform multi-threaded code, I checked the 
thread support code in GCC 3 and GCC 2. While the nice SGI STL (in GCC 
2) use Critical Section for Win32 thread support, libstdc++-v3 uses 
Windows Mutexes for STL locks (in gthr-default.h of MinGW). It is known 
that Critical Sections are more efficient. Some benchmarks can be found 
on the Internet. Could we use Critical Sections, as in GCC 2?

Best regards,

Wu Yongwei