Cygwin: proper executables instead of symlinks

.github/workflows/test.yml

@@ -52,7 +52,6 @@ jobs:
         if: matrix.cygwin
 
       - name: Set up Clang
-        id: setup
         uses: ./
         with:
           platform: '${{ matrix.platform }}'
@@ -65,16 +64,14 @@ jobs:
               $flags += '-m32'
           }
           $flags += @(
-              '-x', 'c++',
               '-std=c++14',
               '-o', 'foo.exe',
-              'foo.cpp',
-              '-lstdc++'
+              'foo.cpp'
           )
           if ('${{ runner.os }}' -eq 'Linux') {
               $flags += '-lpthread'
           }
-          & '${{ steps.setup.outputs.clangxx }}' $flags
+          clang++ $flags
 
       - name: Run foo.exe
         run: |

action.yml

@@ -11,19 +11,10 @@ inputs:
     required: false
     default: 0
 
-outputs:
-  clang:
-    description: clang executable name or path
-    value: '${{ steps.setup.outputs.clang }}'
-  clangxx:
-    description: clang++ executable name or path
-    value: '${{ steps.setup.outputs.clangxx }}'
-
 runs:
   using: composite
   steps:
-    - id: setup
-      run: |
+    - run: |
         New-Variable os -Value '${{ runner.os }}' -Option Constant
 
         New-Variable linux_host -Value ($os -eq 'Linux') -Option Constant
@@ -41,6 +32,18 @@ runs:
             }
         }
 
+        function Convert-CygwinPath {
+            # Like cygpath -wa, but don't resolve symlinks.
+            param(
+                [Parameter(Mandatory=$true)]
+                [string] $Path
+            )
+            $Path = realpath.exe --no-symlinks -- $Path
+            $dirname = dirname.exe -- $Path
+            $dirname = cygpath.exe -wa $dirname
+            Join-Path $dirname (Split-Path $Path -Leaf)
+        }
+
         if ($linux_host) {
             sudo apt update
             if ($x64) {
@@ -48,9 +51,6 @@ runs:
             } else {
                 sudo apt install -y clang g++-multilib
             }
-
-            echo "::set-output name=clang::clang"
-            echo "::set-output name=clangxx::clang++"
         } elseif ($cygwin_host) {
             if (!$x64) {
                 echo @'
@@ -63,25 +63,29 @@ runs:
             $choco = Locate-Choco
 
             # IDK why, but without libiconv-devel, even a "Hello, world!"
-            # C++ app cannot be compiled as of December 2020.
-            # Also, libstdc++ is required, and for simplicity's sake, gcc-g++
-            # is installed.
+            # C++ app cannot be compiled as of December 2020. Also, libstdc++
+            # is required; it's simpler to install gcc-g++ for all the
+            # dependencies.
             & $choco install -y --no-progress --source=cygwin clang libiconv-devel gcc-g++
 
-            # clang/clang++ are symlinks on Cygwin, pointing to clang-VERSION.exe.
-            $clang = cygpath.exe -wa (readlink.exe --canonicalize-existing /usr/bin/clang)
-            $clangxx = cygpath.exe -wa (readlink.exe --canonicalize-existing /usr/bin/clang++)
-
-            echo "::set-output name=clang::$clang"
-            echo "::set-output name=clangxx::$clangxx"
+            # clang/clang++ are Cygwin symlinks, pointing to clang-X.exe. It's
+            # convenient to make proper executables instead so that they can be
+            # called from Windows' command prompt.
+            find.exe /usr/bin -iname 'clang*' -type l | %{
+                $link_path = $_
+                $dest_path = readlink.exe --canonicalize-existing -- $link_path
+                $link_winpath = Convert-CygwinPath $link_path
+                $dest_winpath = Convert-CygwinPath $dest_path
+                echo "Removing symlink: $link_winpath"
+                Remove-Item $link_winpath -Force
+                echo "Creating hardlink '$link_winpath.exe', pointing to '$dest_winpath'"
+                New-Item -ItemType HardLink -Path "$link_winpath.exe" -Value $dest_winpath | Out-Null
+            }
         } elseif ($windows_host) {
             $choco = Locate-Choco
 
             & $choco install -y --no-progress llvm
             echo (Join-Path $env:ProgramFiles LLVM bin) >> $env:GITHUB_PATH
-
-            echo "::set-output name=clang::clang"
-            echo "::set-output name=clangxx::clang++"
         } else {
             throw "Sorry, installing Clang is unsupported on $os"
         }