chore(common): create flag file without node

Addresses code review comments.

Author: ermshiperete

.gitignore

@@ -183,3 +183,6 @@ lcov.info
 /keyman*.buildinfo
 /keyman*.changes
 /keyman*.tar.?z
+
+# flag file for build script
+.configured

common/tools/hextobin/build.sh

@@ -11,7 +11,7 @@ THIS_SCRIPT="$(readlink -f "${BASH_SOURCE[0]}")"
 
 builder_describe "Build hextobin" clean configure build
 builder_describe_outputs \
-  configure /common/tools/hextobin/build/.configured \
+  configure /common/tools/hextobin/.configured \
   build     /common/tools/hextobin/build/index.js
 
 builder_parse "$@"

common/tools/hextobin/package.json

@@ -17,6 +17,6 @@
     "hextobin": "build/hextobin.js"
   },
   "scripts": {
-    "postinstall": "node --eval \"const fs =require('fs'); const path = require('path'); var dir = 'build'; if (!fs.existsSync(dir)) { fs.mkdirSync(dir); } fs.writeFileSync(path.join(dir, '.configured'), '');\""
+    "postinstall": "echo configured > .configured"
   }
 }