ci: add verbose option to manual build workflow

.github/workflows/manual-build.yml

@@ -31,6 +31,9 @@ on:
       min-os-ver-arm:
         description: 'macOS deployment version for ARM'
         type: string
+      verbose:
+        description: 'Verbose build output'
+        type: boolean
       hack-static-moltenvk:
         description: 'Link with static MoltenVK library'
         type: boolean
@@ -71,6 +74,10 @@ jobs:
           	BUILD_CMDLINE+=' --quasi-glib'
           fi
           
+          if [ "${{ inputs.verbose }}" == 'true' ]; then
+          	BUILD_CMDLINE+=' --verbose'
+          fi
+
           echo "Build command line:"
           echo "> ${BUILD_CMDLINE}"