fix: do not install git if already installed

Author: aminya

dist/legacy/setup-cpp.js

@@ -1,8 +1,9 @@
 import { existsSync } from "fs"
-import { warning } from "ci-log"
+import { info, warning } from "ci-log"
 import { addPath } from "envosman"
 import { installAptPack } from "setup-apt"
 import { installBrewPack } from "setup-brew"
+import which from "which"
 import { rcOptions } from "../cli-options.js"
 import { hasDnf } from "../utils/env/hasDnf.js"
 import { isArch } from "../utils/env/isArch.js"
@@ -13,6 +14,12 @@ import { setupPacmanPack } from "../utils/setup/setupPacmanPack.js"
 
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
 export async function setupGit(version: string, _setupDir: string, _arch: string) {
+  const git = await which("git", { nothrow: true })
+  if (git !== null) {
+    info(`Git already installed at ${git}`)
+    return
+  }
+
   switch (process.platform) {
     case "win32": {
       const result = await setupChocoPack("git", version)