Delete vendored code and update CI to Go 1.13 (#158)

As the Go community transitions to using the modules ecosystem,
we want to only support one way of managing dependencies.
So this change moves to only using Go modules for dependency management.

This means that our effective minimum Go version increases to Go 1.11.
To account for this, we also update:
  - the documentation
  - Makefile
  - CI scripts

1 files changed, 0 insertions, 39 deletions

diff --git a/vendor/golang.org/x/sys/unix/gccgo_c.c b/vendor/golang.org/x/sys/unix/gccgo_c.c
deleted file mode 100644
index c44730c..0000000
--- a/vendor/golang.org/x/sys/unix/gccgo_c.c
+++ /dev/null
@@ -1,39 +0,0 @@
-// 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
-// +build !aix
-
-#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;
-}
-
-uintptr_t
-gccgoRealSyscallNoError(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)
-{
-	return syscall(trap, a1, a2, a3, a4, a5, a6, a7, a8, a9);
-}