Hello, In winpthreads's pthread_compat.h[1] we have the following code, which is only used when it is included with MSVC:
``` #ifdef _WIN64 typedef __int64 pid_t; #else typedef int pid_t; #endif ``` If project's configure.ac invokes AC_TYPE_PID_T, since MSVC's header file do not declare pid_t, the check will fail and it will add ``` #define pid_t int // or #define pid_t __int64 ``` to generated config.h. Later, if both config.h and pthread_compat.h are included, this will result in compilation error since above code, after preprocessing, becomes ``` typedef int int; // or typedef __int64 __int64; ``` Can AC_TYPE_PID_T be changed to use `typedef` instead of `#define` to provide definition of `pid_t`? If this is not feasible, we will resort to either undefining `pid_t` or guarding the winpthreads's typedefs. - Kirill Makurin [1] https://github.com/mingw-w64/mingw-w64/blob/master/mingw-w64-libraries/winpthreads/include/pthread_compat.h
