Cross compile for Linux, MacOS and Windows on CI (#2665)

src/jv_thread.h

@@ -2,6 +2,7 @@
 #define JV_THREAD_H
 
 #ifdef WIN32
+#ifndef __MINGW32__
 #include <windows.h>
 #include <winnt.h>
 #include <errno.h>
@@ -69,4 +70,7 @@ void *pthread_getspecific(pthread_key_t);
 #else
 #include <pthread.h>
 #endif
+#else
+#include <pthread.h>
+#endif
 #endif /* JV_THREAD_H */