Use more robust pre-commit hook.

.githooks/pre-commit

@@ -1,13 +1,21 @@
 #!/usr/bin/env bash
 set -e
 
-filesToFormat=$(
-  git --no-pager diff --name-status --no-color --cached | \
-    awk '$1 != "D" && $2 ~ /\.c$|\.h$/ {print $NF}'
+STAGED=$(
+  git --no-pager diff --name-only --no-color --cached --diff-filter=d |
+    # Remove quotations used to surrounding filenames with special characters.
+    sed -e "s/^\"//" -e "s/\"$//g"
 )
 
-for path in $filesToFormat
+TARGETS=()
+while IFS= read -r FILENAME
 do
-  clang-format -i "$path"
-  git add "$path"
-done;
+  if [[ "$FILENAME" =~ .*\.c ]] || [[ "$FILENAME" == .*\.h ]]; then
+    TARGETS+=("${FILENAME}")
+  fi
+done <<< "$STAGED"
+
+if (( ${#TARGETS[@]} )); then
+  clang-format -i "${TARGETS[@]}"
+  git add "${TARGETS[@]}"
+fi