Add a couple of things to gitignore

firmware/.gitignore

@@ -9,6 +9,9 @@ gdbscript-custom
 # The output directory
 out/
 
+# things
+tools/
+
 # Intermediate compilation files
 *.o
 
@@ -22,4 +25,7 @@ TAGS
 tools/verification/ctypesgen
 
 # Compiled python
-*.pyc
+*.pyc
+
+# Compile commands
+compile_commands.json