CI: make sure that directories which contain whitespace do work

.github/workflows/test-alpine-linux.yml

@@ -6,7 +6,7 @@
 name: 'Test - Minimal Alpine build'
 on: [workflow_dispatch]
 jobs:
-  job-alpine-clang:
+  job-alpine-clang: # uses cmake + make
     strategy: { matrix: { container: ['alpine:edge','i386/alpine:edge'] } }
     name: ${{ format('clang {0}', matrix.container) }}
     runs-on: ubuntu-latest
@@ -31,7 +31,8 @@ jobs:
         with:
           name: ${{ env.artifact_name }}
           path: 'upx*/build/*/upx'
-  job-alpine-gcc:
+
+  job-alpine-gcc: # uses cmake + make
     strategy: { matrix: { container: ['alpine:edge','i386/alpine:edge'] } }
     name: ${{ format('gcc {0}', matrix.container) }}
     runs-on: ubuntu-latest
@@ -56,3 +57,31 @@ jobs:
         with:
           name: ${{ env.artifact_name }}
           path: 'upx*/build/*/upx'
+
+  job-alpine-by-hand: # uses shell
+    # and also uses a subdirectory "upx with space" in order to detect possible quoting issues
+    strategy: { matrix: { container: ['alpine:3.9','alpine:edge'] } }
+    name: ${{ format('gcc by-hand {0}', matrix.container) }}
+    runs-on: ubuntu-latest
+    container: ${{ matrix.container }}
+    steps:
+      - name: ${{ format('Install packages {0}', matrix.container) }}
+        run: |
+          apk update && apk upgrade && apk add bash dash g++ git mksh zsh
+          # this seems to be needed when running in a container (beause of UID mismatch??)
+          git config --global --add safe.directory '*'
+      - name: 'Check out code'
+        uses: actions/checkout@v3
+        with:
+          submodules: true
+          path: 'upx with space'
+      - name: 'Build by-hand with bash'
+        run: 'bash "./upx with space/misc/scripts/build_upx_by_hand.sh"'
+      - name: 'Build by-hand with busybox sh'
+        run: 'busybox sh "./upx with space/misc/scripts/build_upx_by_hand.sh"'
+      - name: 'Build by-hand with dash'
+        run: 'dash "./upx with space/misc/scripts/build_upx_by_hand.sh"'
+      - name: 'Build by-hand with mksh'
+        run: 'mksh "./upx with space/misc/scripts/build_upx_by_hand.sh"'
+      - name: 'Build by-hand with zsh'
+        run: 'zsh "./upx with space/misc/scripts/build_upx_by_hand.sh"'