add CI github action

.github/workflows/ci.yml

@@ -0,0 +1,38 @@
+---
+name: CI
+on:
+  pull_request:
+    branches:
+      - main
+  push:
+    branches:
+      - main
+
+jobs:
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: true
+      matrix:
+        go: ["stable", "oldstable"]
+    timeout-minutes: 5
+
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-go@v5
+        with:
+          go-version: ${{ matrix.go }}
+      - run: go version
+      - run: go mod verify
+      - name: go mod tidy
+        run: |
+          go mod tidy
+          git diff --exit-code
+      - run: go vet ./...
+      - name: go fmt
+        run: |
+          go fmt ./...
+          git diff --exit-code
+      - name: go test
+        run: go test -v -count=1 -shuffle=on ./...

.golangci.yml

@@ -0,0 +1 @@
+run: {}

Makefile

@@ -0,0 +1,40 @@
+.DEFAULT_GOAL = check
+.PHONY: FORCE
+
+CC = /usr/local/musl/bin/musl-gcc
+GOFLAGS = -ldflags '-linkmode external -extldflags "-static"'
+OUTDIR = bin
+TESTGEN_BINARY = $(OUTDIR)/testgen
+
+build-testgen: $(TESTGEN_BINARY)
+.PHONY: build-testgen
+
+clean:
+	rm -f $(TESTGEN_BINARY)
+.PHONY: clean
+
+fmt:
+	go fmt ./...
+.PHONY: fmt
+
+vet:
+	go vet ./...
+.PHONY: vet
+
+test:
+	go test -v -p=4 ./...
+.PHONY: test
+
+check: fmt vet test
+.PHONY: check
+
+$(TESTGEN_BINARY): FORCE
+	@mkdir -p $(OUTDIR)
+	CC=$(CC) go build $(GOFLAGS) -o $@ ./cmd/testgen/main.go
+
+deps: FORCE
+	go mod verify
+	go mod tidy
+
+all: clean deps
+.PHONY: all

cmd/testgen/main.go

@@ -1,3 +1,5 @@
+//go:build linux
+
 package main
 
 import (

internal/testgen/cgetopt.go

@@ -179,6 +179,10 @@ func cGetOpt(cArgc C.int, cArgv []*C.char, optstring string, longoptstring strin
 	name := parseName(cLongoptions, char, optopt, flag)
 	mutArgs := copyCArgv(cArgc, cArgv)
 
+	if err == "-1" {
+		optarg = ""
+	}
+
 	if (err == "?" || err == ":") && (char == "" && name == "") {
 		val := strings.TrimPrefix(curr_arg, "-")
 		val = strings.TrimPrefix(val, "-")