Added arm64 support for NetBSD

src/gb/gb.h

@@ -256,6 +256,7 @@ extern "C" {
 
 #if defined(GB_SYSTEM_NETBSD)
 	#include <stdio.h>
+	#include <lwp.h>
 	#define lseek64 lseek
 #endif
 
@@ -3027,6 +3028,8 @@ gb_inline u32 gb_thread_current_id(void) {
 	thread_id = find_thread(NULL);
 #elif defined(GB_SYSTEM_FREEBSD)
 	thread_id = pthread_getthreadid_np();
+#elif defined(GB_SYSTEM_NETBSD)
+	thread_id = (u32)_lwp_self();
 #else
 	#error Unsupported architecture for gb_thread_current_id()
 #endif