[PATCH 6/8] Addition of clang nullability qualifiers.

[Sebastian Huber <sebastian.huber@embedded-brains.de>]

From: pfg <pfg@FreeBSD.org>

For consistency with the qualifiers added in r310977, define a new
qualifier _Null_unspecified which is also defined in clang 3.7+.

Add two new macros:
__NULLABILITY_PRAGMA_PUSH
__NULLABILITY_PRAGMA_POP

These are for use in headers when we want avoid noisy warnings if
some pointers are left without nullability annotations.

These are added with way ahead of their first use to teach the GCC
ports headers of their existance before their first use.
---
 newlib/libc/include/sys/cdefs.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/newlib/libc/include/sys/cdefs.h b/newlib/libc/include/sys/cdefs.h
index 679425a..fa1692c 100644
--- a/newlib/libc/include/sys/cdefs.h
+++ b/newlib/libc/include/sys/cdefs.h
@@ -634,6 +634,13 @@
 #if !(defined(__clang__) && __has_feature(nullability))
 #define	_Nonnull
 #define	_Nullable
+#define	_Null_unspecified
+#define	__NULLABILITY_PRAGMA_PUSH
+#define	__NULLABILITY_PRAGMA_POP
+#else
+#define	__NULLABILITY_PRAGMA_PUSH _Pragma("clang diagnostic push")	\
+	_Pragma("clang diagnostic ignored \"-Wnullability-completeness\"")
+#define	__NULLABILITY_PRAGMA_POP _Pragma("clang diagnostic pop")
 #endif
 
 /*
-- 
1.8.4.5