Linux: port the emulator to a working state on Linux (#117)

Linux: port the emulator to a working state

src/graphics/host_gpu/regionManager.h

@@ -18,6 +18,9 @@
 #undef max
 #elif defined(__APPLE__)
 #include <pthread.h>
+#elif defined(__linux__)
+#include <sys/syscall.h>
+#include <unistd.h>
 #endif
 
 namespace Libs::Graphics {
@@ -54,6 +57,9 @@ private:
 #elif defined(__APPLE__)
 		// mach thread port is a nonzero per-thread id (0 is the "no owner" sentinel).
 		return static_cast<uint32_t>(pthread_mach_thread_np(pthread_self()));
+#elif defined(__linux__)
+		static thread_local const uint32_t tid = static_cast<uint32_t>(::syscall(SYS_gettid));
+		return tid;
 #else
 		EXIT("region tracking thread identity is unsupported on this platform\n");
 #endif