Merge #130: Travis: Add Go 1.13.x, 1.14.x, 1.15.x

39a0d8d25e Travis: Disable darwin/386 for Go 1.15+ (Jeremy Rand)
a1f234a64f Travis: Add Go 1.13.x, 1.14.x, 1.15.x (Jeremy Rand)

Pull request description:

Top commit has no ACKs.

Tree-SHA512: d18576050a2e594d64a6549d572ea7e033877a945603b8de8c548e0e48558b3146f6789fd6b38a7f6bb6bcf766ad01316b89cd961fe5c662a2d47d049deae569

.travis.yml

@@ -4,6 +4,9 @@ go:
   - "1.11.x"
   - "1.12.5"
   - "1.12.x"
+  - "1.13.x"
+  - "1.14.x"
+  - "1.15.x"
   - "1.x"
   - "master"
 

.travis/script

@@ -90,7 +90,15 @@ gox -tags="$GOX_TAGS" -parallel=$GOX_PARA -cgo -osarch 'linux/386 linux/amd64' -
 RESULT1=$?
 
 # non-cgo crosscompile
-gox -tags="$GOX_TAGS" -parallel=$GOX_PARA -osarch 'darwin/386 darwin/amd64 linux/arm linux/arm64 linux/ppc64 linux/ppc64le freebsd/386 freebsd/amd64 freebsd/arm openbsd/386 openbsd/amd64 netbsd/386 netbsd/amd64 netbsd/arm dragonfly/amd64 solaris/amd64 windows/386 windows/amd64' -output "$GOPATH/releasing/idist/ncdns-$TRAVIS_TAG-{{.OS}}_{{.Arch}}/bin/{{.Dir}}" $REPOS
+# darwin/386 was removed in Go 1.15
+if [[ "$(go version)" =~ go1.[56789] ]]; then
+  GOX_OPTIONAL_TARGETS="darwin/386 "
+elif [[ "$(go version)" =~ go1.1[01234] ]]; then
+  GOX_OPTIONAL_TARGETS="darwin/386 "
+else
+  GOX_OPTIONAL_TARGETS=""
+fi
+gox -tags="$GOX_TAGS" -parallel=$GOX_PARA -osarch "${GOX_OPTIONAL_TARGETS}darwin/amd64 linux/arm linux/arm64 linux/ppc64 linux/ppc64le freebsd/386 freebsd/amd64 freebsd/arm openbsd/386 openbsd/amd64 netbsd/386 netbsd/amd64 netbsd/arm dragonfly/amd64 solaris/amd64 windows/386 windows/amd64" -output "$GOPATH/releasing/idist/ncdns-$TRAVIS_TAG-{{.OS}}_{{.Arch}}/bin/{{.Dir}}" $REPOS
 RESULT2=$?
 
 echo cgo crosscompile exited with code $RESULT1