Annotate no_return and returns_twice functions.
When building the bionic tests, we use -fno-builtins, which turns off
clang's recognition of vfork as a magical function that can return
twice. Explicitly annotate our returns_twice functions to ensure that
we generate correct code even in -fno-builtins (and while we're at it,
annotate the no_return functions as well, so we generate faster code).
Bug: http://b/131856005
Test: treehugger
Change-Id: I465f8042a965f0c7c03caa5f17af67deea8f5d9d
diff --git a/libc/include/unistd.h b/libc/include/unistd.h
index 90173aa..9000407 100644
--- a/libc/include/unistd.h
+++ b/libc/include/unistd.h
@@ -78,7 +78,7 @@
__noreturn void _exit(int __status);
pid_t fork(void);
-pid_t vfork(void);
+pid_t vfork(void) __returns_twice;
pid_t getpid(void);
pid_t gettid(void) __attribute_const__;
pid_t getpgid(pid_t __pid);