[eclint] only check non-ignored files

Author: ljharb

package.json

@@ -15,7 +15,7 @@
     "test/installation/iojs": "shell=$(basename -- $(ps -o comm= $(ps -o ppid= -p $PPID)) | sed 's/^-//'); make TEST_SUITE=installation_iojs test-$shell",
     "test/sourcing": "shell=$(basename -- $(ps -o comm= $(ps -o ppid= -p $PPID)) | sed 's/^-//'); make TEST_SUITE=sourcing test-$shell",
     "doctoc": "doctoc --title='## Table of Contents' --github README.md",
-    "eclint": "eclint check ."
+    "eclint": "eclint check $(git ls-tree --name-only HEAD | xargs)"
   },
   "repository": {
     "type": "git",