Add keymap wrappers for introspection into the keymap.

[tzarc]

Description

Adds some APIs for getting the number of layers defined in keymap and encoder map.
Should be useful for XAP to return extent information without requiring a #define.

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[masiullah]

I am getting the below error when compiling a userspace keymap, the keymap used to work fine earlier but now it is not working

Compiling: quantum/keymap_introspection.c quantum/keymap_introspection.c: In function 'keymap_layer_count':
quantum/keymap_introspection.c:9:45: error: 'keymaps' undeclared (first use in this function)
9 | #define NUM_KEYMAP_LAYERS ((uint8_t)(sizeof(keymaps) / ((MATRIX_ROWS) * (MATRIX_COLS) * sizeof(uint16_t))))

When I remove the code at line 406 in build_keyboard.mk then it works. Is there something I am missing that I need to do to make this work without build_keyboard changes

line 406 in build_keyboard.mk
$(QUANTUM_DIR)/keymap_introspection.c \

I am able to reproduce this using the below command and it is also happening to a simple user space keymap I created for myself
make splitkb/kyria/rev1:manna-harbour_miryoku

[tzarc]

Seems that keymap does some weird stuff with how it locates the keymap array.
Will have a look and raise a bugfix later today.

[drzony]

This approach breaks compile_commads.json since keymap.c is included instead of being compiled separately