vendor: adding in golang.org/x/sys/unix package

This commit adds in the golang.org/x/sys/unix package. This package
provides a low-level interface to unix syscalls. We will uses this
package instead of the built-in "syscall" package because the syscall
package is locked down (https://golang.org/pkg/syscall) and is not
exposing any new kernel functionality.

In fact, this is actually a patched version of the x/sys/unix package
pending review (first part: https://go-review.googlesource.com/c/37943).
The version included in this commit exposes all of the filesystem
encryption kernel interfaces to Go code.

Change-Id: Ic5f9c98b858ccb00db97502c9a60e9249aa8ba38

1 files changed, 41 insertions, 0 deletions

diff --git a/vendor/golang.org/x/sys/unix/gccgo_c.c b/vendor/golang.org/x/sys/unix/gccgo_c.c
new file mode 100644
index 0000000..07f6be0
--- /dev/null
+++ b/vendor/golang.org/x/sys/unix/gccgo_c.c
@@ -0,0 +1,41 @@
+// Copyright 2015 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build gccgo
+
+#include <errno.h>
+#include <stdint.h>
+#include <unistd.h>
+
+#define _STRINGIFY2_(x) #x
+#define _STRINGIFY_(x) _STRINGIFY2_(x)
+#define GOSYM_PREFIX _STRINGIFY_(__USER_LABEL_PREFIX__)
+
+// Call syscall from C code because the gccgo support for calling from
+// Go to C does not support varargs functions.
+
+struct ret {
+	uintptr_t r;
+	uintptr_t err;
+};
+
+struct ret
+gccgoRealSyscall(uintptr_t trap, uintptr_t a1, uintptr_t a2, uintptr_t a3, uintptr_t a4, uintptr_t a5, uintptr_t a6, uintptr_t a7, uintptr_t a8, uintptr_t a9)
+{
+	struct ret r;
+
+	errno = 0;
+	r.r = syscall(trap, a1, a2, a3, a4, a5, a6, a7, a8, a9);
+	r.err = errno;
+	return r;
+}
+
+// Define the use function in C so that it is not inlined.
+
+extern void use(void *) __asm__ (GOSYM_PREFIX GOPKGPATH ".use") __attribute__((noinline));
+
+void
+use(void *p __attribute__ ((unused)))
+{
+}