Make it possible to build bionic with -I instead of -isystem.
Various things:
* work around -Wnullability-completeness.
* use C++ casts in C++ and C casts in C.
* stop using attributes clang doesn't support (such as `warning`).
* remove duplicate definitions of XATTR_CREATE and XATTR_REPLACE.
Change-Id: I07649e46275b28a23ca477deea119fe843999533
diff --git a/libc/upstream-netbsd/android/include/netbsd-compat.h b/libc/upstream-netbsd/android/include/netbsd-compat.h
index 665d65e..cc0f71f 100644
--- a/libc/upstream-netbsd/android/include/netbsd-compat.h
+++ b/libc/upstream-netbsd/android/include/netbsd-compat.h
@@ -25,6 +25,17 @@
// that they don't actually test or ship with this.
#define _DIAGASSERT(e) /* nothing */
+/*
+ * The following macro is used to remove const cast-away warnings
+ * from gcc -Wcast-qual; it should be used with caution because it
+ * can hide valid errors; in particular most valid uses are in
+ * situations where the API requires it, not to cast away string
+ * constants. We don't use *intptr_t on purpose here and we are
+ * explicit about unsigned long so that we don't have additional
+ * dependencies.
+ */
+#define __UNCONST(a) ((void *)(unsigned long)(const void *)(a))
+
// TODO: we don't yet have thread-safe environment variables.
#define __readlockenv() 0
#define __unlockenv() 0