Add additional patches for a more warning-free build

See also: lancaster-university/microbit-dal#467

patches/silence_cmake_force_cxx.patch

@@ -0,0 +1,25 @@
+Author: wdoekes
+Date: 2022-05-01
+Description: silence CMake complaining about CMAKE_FORCE_CXX_COMPILER
+ It sure looks like more cmake code could be removed, but replacing this
+ silences these warnings:
+ CMake Deprecation Warning at CMakeForceCompiler.cmake:75 (message):
+  The CMAKE_FORCE_C_COMPILER macro is deprecated.  Instead just set
+  CMAKE_C_COMPILER and allow CMake to identify the compiler.
+
+--- a/yotta_targets/mbed-gcc/CMake/toolchain.cmake	2022-05-01 18:41:02.312968861 +0200
++++ b/yotta_targets/mbed-gcc/CMake/toolchain.cmake	2022-05-01 18:46:50.216029108 +0200
+@@ -72,11 +72,8 @@ set(CMAKE_MODULE_LINKER_FLAGS_INIT
+ )
+ set(CMAKE_EXE_LINKER_FLAGS_INIT "${CMAKE_MODULE_LINKER_FLAGS_INIT} -Wl,-wrap,main") 
+
+-# Set the compiler to ARM-GCC
+-include(CMakeForceCompiler)
+-
+-cmake_force_c_compiler("${ARM_NONE_EABI_GCC}" GNU)
+-cmake_force_cxx_compiler("${ARM_NONE_EABI_GPP}" GNU)
++set(CMAKE_C_COMPILER arm-none-eabi-gcc)
++set(CMAKE_CXX_COMPILER arm-none-eabi-g++)
+
+ # post-process elf files into .bin files:
+ function(yotta_apply_target_rules target_type target_name)

patches/silence_cmake_yotta_cmp0017.patch

@@ -0,0 +1,20 @@
+Author: wdoekes
+Date: 2022-05-01
+Description: silence CMake complaining about CMP0017 being removed
+ I'm not sure if we need that CMP0017 ordering. Without it, the build
+ still works, so removing might be fine. Before, we had these warnings:
+ CMake Deprecation Warning at CMakeLists.txt:16 (cmake_policy):
+  The OLD behavior for policy CMP0017 will be removed from a future version
+  of CMake.
+
+--- /usr/share/yotta/yotta/lib/templates/base_CMakeLists.txt	2022-05-01 18:44:50.864336461 +0200
++++ /usr/share/yotta/yotta/lib/templates/base_CMakeLists.txt	2022-05-01 18:44:54.640326530 +0200
+@@ -14,7 +14,7 @@ add_custom_target(all_tests)
+
+ # always use the CMAKE_MODULE_PATH-provided .cmake files, even when including
+ # from system directories:
+-cmake_policy(SET CMP0017 OLD)
++#cmake_policy(SET CMP0017 OLD)
+
+ # toolchain file for {{ target_name }}
+ set(CMAKE_TOOLCHAIN_FILE "{{ toolchain_file | replaceBackslashes }}")