Add usermod.cmake files for building against upstream usermod micropython usermod branch

Only *one* usermod directory can be specified, so the build command becomes something like:

make USER_C_MODULES=/path/to/pimoroni-pico/micropython/modules/

The `usermod.cmake` in the "modules" dir will then include all of the modules. Comment lines our here to disable them.

No need to configure anythign in `mpconfigport.h` since the defines are set by the `usermod.cmake` files.

micropython/modules/pico_rgb_keypad/usermod.cmake

@@ -0,0 +1,17 @@
+add_library(usermod_pico_rgb_keypad INTERFACE)
+
+target_sources(usermod_pico_rgb_keypad INTERFACE
+    ${CMAKE_CURRENT_LIST_DIR}/pico_rgb_keypad.c
+    ${CMAKE_CURRENT_LIST_DIR}/pico_rgb_keypad.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/../../../libraries/pico_rgb_keypad/pico_rgb_keypad.cpp
+)
+
+target_include_directories(usermod_pico_rgb_keypad INTERFACE
+    ${CMAKE_CURRENT_LIST_DIR}
+)
+
+target_compile_definitions(usermod_pico_rgb_keypad INTERFACE
+    -DMODULE_PICOKEYPAD_ENABLED=1
+)
+
+target_link_libraries(usermod INTERFACE usermod_pico_rgb_keypad)

micropython/modules/pico_scroll/usermod.cmake

@@ -0,0 +1,17 @@
+add_library(usermod_pico_scroll INTERFACE)
+
+target_sources(usermod_pico_scroll INTERFACE
+    ${CMAKE_CURRENT_LIST_DIR}/pico_scroll.c
+    ${CMAKE_CURRENT_LIST_DIR}/pico_scroll.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/../../../libraries/pico_scroll/pico_scroll.cpp
+)
+
+target_include_directories(usermod_pico_scroll INTERFACE
+    ${CMAKE_CURRENT_LIST_DIR}
+)
+
+target_compile_definitions(usermod_pico_scroll INTERFACE
+    -DMODULE_PICOSCROLL_ENABLED=1
+)
+
+target_link_libraries(usermod INTERFACE usermod_pico_scroll)

micropython/modules/pico_unicorn/usermod.cmake

@@ -0,0 +1,19 @@
+add_library(usermod_pico_unicorn INTERFACE)
+
+target_sources(usermod_pico_unicorn INTERFACE
+    ${CMAKE_CURRENT_LIST_DIR}/pico_unicorn.c
+    ${CMAKE_CURRENT_LIST_DIR}/pico_unicorn.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/../../../libraries/pico_unicorn/pico_unicorn.cpp
+)
+
+pico_generate_pio_header(usermod_pico_unicorn ${CMAKE_CURRENT_LIST_DIR}/../../../libraries/pico_unicorn/pico_unicorn.pio)
+
+target_include_directories(usermod_pico_unicorn INTERFACE
+    ${CMAKE_CURRENT_LIST_DIR}
+)
+
+target_compile_definitions(usermod_pico_unicorn INTERFACE
+    -DMODULE_PICOUNICORN_ENABLED=1
+)
+
+target_link_libraries(usermod INTERFACE usermod_pico_unicorn)

micropython/modules/usermod.cmake

@@ -0,0 +1,3 @@
+include(${CMAKE_CURRENT_LIST_DIR}/pico_scroll/usermod.cmake)
+include(${CMAKE_CURRENT_LIST_DIR}/pico_rgb_keypad/usermod.cmake)
+include(${CMAKE_CURRENT_LIST_DIR}/pico_unicorn/usermod.cmake)