dist/tools/cppcheck: Allow individual files to be cppchecked

dist/tools/cppcheck/check.sh

@@ -19,7 +19,28 @@ else
     DEFAULT_SUPPRESSIONS=--suppress="unusedStructMember"
 fi
 
-FILES=$(changed_files)
+FILES=""
+CPPCHECK_OPTIONS=""
+IN_FILES_SECTION=false
+while [ $# -gt 0 ]; do
+    if [ "$1" = "--" ]; then
+        IN_FILES_SECTION=true
+        shift
+        continue
+    fi
+
+    if [ "$IN_FILES_SECTION" = false ]; then
+        CPPCHECK_OPTIONS="${CPPCHECK_OPTIONS} $1"
+    else
+        FILES="${FILES} $1"
+    fi
+
+    shift
+done
+
+if [ -z "${FILES}" ]; then
+    FILES=$(changed_files)
+fi
 
 if [ -z "${FILES}" ]; then
     exit
@@ -28,4 +49,4 @@ fi
 # TODO: switch back to 8 jobs when/if cppcheck issue is resolved
 cppcheck --std=c99 --enable=style --force --error-exitcode=2 --quiet -j 1 \
          --template "{file}:{line}: {severity} ({id}): {message}"         \
-         --inline-suppr ${DEFAULT_SUPPRESSIONS} ${@} ${FILES}
+         --inline-suppr ${DEFAULT_SUPPRESSIONS} ${CPPCHECK_OPTIONS} ${@} ${FILES}