Better macOS postinstall script

app/bin/build.js

@@ -168,6 +168,8 @@ function packageDarwin (platform) {
       , manifestName
       , componentName
       , packageId: `tf.matt.${applicationName}`
+      , executablePath: executablePath[platform]
+      , manifestPath: manifestPath[platform]
     };
 
     // Template paths

app/packaging/mac/scripts/postinstall

@@ -3,9 +3,9 @@
 # If the target location isn't root, we need to rewrite
 # the manifest path to point to the user directory.
 if [ "$2" != "/" ]; then
-	manifestPath=$2"/Library/Application Support/Mozilla/NativeMessagingHosts/{{{manifestName}}}"
-	sed -i.bak 's,"path": "/Library,"path": "'$2'/Library,g' "$manifestPath"
-	rm  "$manifestPath.bak"
+    installedManifestPath=$2"/{{{manifestPath}}}/{{{manifestName}}}"
+    sed -i.bak 's,{{{executablePath}}},'$2'{{{executablePath}}},g' "$installedManifestPath"
+    rm  "$installedManifestPath.bak"
 fi
 
 exit 0