tools: make ./v symlink work platform independent in CI (part 1) (#21453)

.github/workflows/check_symlink_works.yml

@@ -16,18 +16,20 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  test-sudo:
+  test:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-20.04, macos-13]
+        os: [ubuntu-20.04, macos-13, windows-2019]
       fail-fast: false
     steps:
       - uses: actions/checkout@v4
-      - name: Build V
-        run: make -j4
-      - name: Symlink
-        run: sudo ./v symlink
+      - name: Build and symlink (Windows)
+        if: runner.os == 'Windows'
+        run: ./make.bat && ./v symlink
+      - name: Build and symlink
+        if: runner.os != 'Windows'
+        run: make -j4 && sudo ./v symlink
       - name: Check if V is usable
         run: |
           pwd

cmd/tools/vsymlink/vsymlink_windows.c.v

@@ -83,6 +83,20 @@ fn setup_symlink() {
 		warn_and_exit('You might need to run this again to have the `v` command in your %PATH%')
 	}
 	C.RegCloseKey(reg_sys_env_handle)
+	if os.getenv('GITHUB_JOB') != '' {
+		// Append V's install location to GITHUBs PATH environment variable.
+		// Resources:
+		// 1. https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#environment-files
+		// 2. https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#setting-an-environment-variable
+		mut content := os.read_file(os.getenv('GITHUB_PATH')) or {
+			eprintln('The `GITHUB_PATH` env variable is not defined.')
+			exit(1)
+		}
+		content += '\n${new_sys_env_path}\n'
+		os.write_file(os.getenv('GITHUB_PATH'), content) or {
+			panic('Failed to write to GITHUB_PATH.')
+		}
+	}
 	println('Done.')
 	println('Note: Restart your shell/IDE to load the new %PATH%.')
 	println('After restarting your shell/IDE, give `v version` a try in another directory!')