.travis, build: drop support for Go 1.8 (need type aliases)

.travis.yml

@@ -3,17 +3,6 @@ go_import_path: github.com/ethereum/go-ethereum
 sudo: false
 matrix:
   include:
-    - os: linux
-      dist: trusty
-      sudo: required
-      go: 1.8.x
-      script:
-        - sudo modprobe fuse
-        - sudo chmod 666 /dev/fuse
-        - sudo chown root:$USER /etc/fuse.conf
-        - go run build/ci.go install
-        - go run build/ci.go test -coverage
-
     - os: linux
       dist: trusty
       sudo: required

build/ci.go

@@ -182,13 +182,13 @@ func doInstall(cmdline []string) {
 	// Check Go version. People regularly open issues about compilation
 	// failure with outdated Go. This should save them the trouble.
 	if !strings.Contains(runtime.Version(), "devel") {
-		// Figure out the minor version number since we can't textually compare (1.10 < 1.8)
+		// Figure out the minor version number since we can't textually compare (1.10 < 1.9)
 		var minor int
 		fmt.Sscanf(strings.TrimPrefix(runtime.Version(), "go1."), "%d", &minor)
 
-		if minor < 8 {
+		if minor < 9 {
 			log.Println("You have Go version", runtime.Version())
-			log.Println("go-ethereum requires at least Go version 1.8 and cannot")
+			log.Println("go-ethereum requires at least Go version 1.9 and cannot")
 			log.Println("be compiled with an earlier version. Please upgrade your Go installation.")
 			os.Exit(1)
 		}
@@ -262,16 +262,6 @@ func goTool(subcmd string, args ...string) *exec.Cmd {
 
 func goToolArch(arch string, cc string, subcmd string, args ...string) *exec.Cmd {
 	cmd := build.GoTool(subcmd, args...)
-	if subcmd == "build" || subcmd == "install" || subcmd == "test" {
-		// Go CGO has a Windows linker error prior to 1.8 (https://github.com/golang/go/issues/8756).
-		// Work around issue by allowing multiple definitions for <1.8 builds.
-		var minor int
-		fmt.Sscanf(strings.TrimPrefix(runtime.Version(), "go1."), "%d", &minor)
-
-		if runtime.GOOS == "windows" && minor < 8 {
-			cmd.Args = append(cmd.Args, []string{"-ldflags", "-extldflags -Wl,--allow-multiple-definition"}...)
-		}
-	}
 	cmd.Env = []string{"GOPATH=" + build.GOPATH()}
 	if arch == "" || arch == runtime.GOARCH {
 		cmd.Env = append(cmd.Env, "GOBIN="+GOBIN)