installer and ci: Throw more errors on failure

This makes it easier to notice when installer generation failed.

.github/workflows/ci.yml

@@ -138,6 +138,7 @@ jobs:
         with:
           name: ${{ matrix.config.name }} - installer
           path: build/Aegisub-*.exe
+          if-no-files-found: error
       
       - name: Upload artifacts - portable.zip
         uses: actions/upload-artifact@v3
@@ -159,3 +160,4 @@ jobs:
         with:
           name: ${{ matrix.config.name }} - installer
           path: build/Aegisub-*.dmg
+          if-no-files-found: error

tools/win-installer-setup.ps1

@@ -69,7 +69,9 @@ if (!(Test-Path ffi-experiments)) {
 	git clone https://github.com/TypesettingTools/ffi-experiments.git
 	Set-Location ffi-experiments
 	meson build -Ddefault_library=static
+	if(!$?) { Exit $LASTEXITCODE }
 	meson compile -C build
+	if(!$?) { Exit $LASTEXITCODE }
 	Set-Location $DepsDir
 }
 
@@ -84,7 +86,9 @@ if (!(Test-Path VC_redist)) {
 # localization
 Set-Location $BuildRoot
 meson compile aegisub-gmo
+if(!$?) { Exit $LASTEXITCODE }
 
 # Invoke InnoSetup
 $IssUrl = Join-Path $InstallerDir "aegisub_depctrl.iss"
 iscc $IssUrl
+if(!$?) { Exit $LASTEXITCODE }