Add __pure2 to a few more functions, most notably gettid and pthread_self.
Change-Id: I7eee9f26f45130038af09d8285782b07f70a996f
diff --git a/libc/include/errno.h b/libc/include/errno.h
index 2e5ce5f..1a36b7a 100644
--- a/libc/include/errno.h
+++ b/libc/include/errno.h
@@ -41,7 +41,7 @@
#endif
/* internal function returning the address of the thread-specific errno */
-extern volatile int* __errno(void);
+extern volatile int* __errno(void) __pure2;
/* a macro expanding to the errno l-value */
#define errno (*__errno())