Update usage of syscall to use the intrinsics

core/sync/sync_linux.odin

@@ -1,16 +1,11 @@
 package sync
 
 import "core:sys/unix"
-
-foreign import libc "system:c"
+import "core:intrinsics"
 
 current_thread_id :: proc "contextless" () -> int {
-	foreign libc {
-		syscall :: proc(number: i32, #c_vararg args: ..any) -> i32 ---
-	}
-
 	SYS_GETTID :: 186;
-	return int(syscall(SYS_GETTID));
+	return int(intrinsics.syscall(SYS_GETTID));
 }