Fix clang-format version checking

scripts/clang-format-check

@@ -1,21 +1,19 @@
 #!/bin/bash
 
-clangformat="clang-format"
-if [ -n "$1" ]; then
-    clangformat="clang-format-$1"
-fi
+CLANG_FORMAT=${CLANG_FORMAT:-clang-format}
+CLANG_FORMAT_VERSION=${CLANG_FORMAT_VERSION:-}
 
-if ! type $clangformat >/dev/null; then
-    # clang-format not found. If running tests, mark this test as
-    # skipped.
+if ! type $CLANG_FORMAT >/dev/null || \
+        ! $CLANG_FORMAT --version | grep -q "version ${CLANG_FORMAT_VERSION}"; then
+    # If running tests, mark this test as skipped.
     exit 77
 fi
 
 errors=0
-paths=$(find . -type f -a '(' -name '*.c' -o -name '*.h' ')')
+paths=$(git ls-files | grep '\.[ch]$')
 for path in $paths; do
     in=$(cat $path)
-    out=$($clangformat $path)
+    out=$($CLANG_FORMAT $path)
 
     if [ "$in" != "$out" ]; then
         diff -u -L $path -L "$path.formatted" $path - <<<$out