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/sys/cdefs.h b/libc/include/sys/cdefs.h
index a919a79..ca9374e 100644
--- a/libc/include/sys/cdefs.h
+++ b/libc/include/sys/cdefs.h
@@ -86,6 +86,7 @@
#define __noreturn __attribute__((__noreturn__))
#define __mallocfunc __attribute__((__malloc__))
#define __packed __attribute__((__packed__))
+#define __returns_twice __attribute__((__returns_twice__))
#define __unused __attribute__((__unused__))
#define __used __attribute__((__used__))