Add go versions, make scripts more resilient

.travis.yml

@@ -1,17 +1,19 @@
+sudo: false
 language: go
-env:
-    global:
-        - VET_VERSIONS="1.6 1.7 1.8 1.9 1.10 tip"
-        - LINT_VERSIONS="1.7 1.8 1.9 1.10 tip"
 go:
-    - "1.4"
-    - "1.5"
-    - "1.6"
-    - "1.7"
-    - "1.8"
-    - "1.9"
-    - "1.10"
+    - "1.4.x"
+    - "1.5.x"
+    - "1.6.x"
+    - "1.7.x"
+    - "1.8.x"
+    - "1.9.x"
+    - "1.10.x"
+    - "1.11.x"
     - tip
+
+git:
+  depth: 1
+
 matrix:
     fast_finish: true
     allow_failures:
@@ -20,10 +22,10 @@ go_import_path: gopkg.in/ldap.v2
 install:
     - go get gopkg.in/asn1-ber.v1
     - go get code.google.com/p/go.tools/cmd/cover || go get golang.org/x/tools/cmd/cover
-    - go get github.com/golang/lint/golint || true
+    - go get github.com/golang/lint/golint || go get golang.org/x/lint/golint || true
     - go build -v ./...
 script:
     - make test
     - make fmt
-    - if [[ "$VET_VERSIONS"  == *"$TRAVIS_GO_VERSION"* ]]; then make vet; fi
-    - if [[ "$LINT_VERSIONS" == *"$TRAVIS_GO_VERSION"* ]]; then make lint; fi
+    - make vet
+    - make lint

Makefile

@@ -36,15 +36,31 @@ fmt:
 
 # Only run on go1.5+
 vet:
-	go tool vet -atomic -bool -copylocks -nilfunc -printf -shadow -rangeloops -unreachable -unsafeptr -unusedresult .
+	@go tool -n vet >/dev/null 2>&1; \
+		if [ $$? -eq 0 ]; then \
+			echo "go vet" ; \
+			go tool vet \
+				-atomic \
+				-bool \
+				-copylocks \
+				-nilfunc \
+				-printf \
+				-shadow \
+				-rangeloops \
+				-unreachable \
+				-unsafeptr \
+				-unusedresult \
+				. ; \
+		fi ;
+
 
 # https://github.com/golang/lint
 # go get github.com/golang/lint/golint
 # Capture output and force failure when there is non-empty output
 # Only run on go1.5+
 lint:
 	@echo golint ./...
-	@OUTPUT=`golint ./... 2>&1`; \
+	@OUTPUT=`command -v golint >/dev/null 2>&1 && golint ./... 2>&1`; \
 	if [ "$$OUTPUT" ]; then \
 		echo "golint errors:"; \
 		echo "$$OUTPUT"; \