cmake: Uniform Avr toolchain build with MK3

- Also set AR/RANLIB in the toolchain
- Fetch GCC version from bootstrap

cmake/AnyAvrGcc.cmake

@@ -72,6 +72,16 @@ set(CMAKE_ASM_COMPILE_OBJECT
     CACHE STRING "" FORCE
     )
 
+set(CMAKE_AR
+    "${BINUTILS_PATH}/${TOOLCHAIN_PREFIX}gcc-ar${EXECUTABLE_SUFFIX}"
+    CACHE FILEPATH "ar" FORCE
+    )
+
+set(CMAKE_RANLIB
+    "${BINUTILS_PATH}/${TOOLCHAIN_PREFIX}gcc-ranlib${EXECUTABLE_SUFFIX}"
+    CACHE FILEPATH "ranlib" FORCE
+    )
+
 set(CMAKE_OBJCOPY
     "${BINUTILS_PATH}/${TOOLCHAIN_PREFIX}objcopy${EXECUTABLE_SUFFIX}"
     CACHE INTERNAL "objcopy tool"

cmake/AvrGcc.cmake

@@ -1,6 +1,4 @@
 get_filename_component(PROJECT_CMAKE_DIR "${CMAKE_CURRENT_LIST_FILE}" DIRECTORY)
-
-set(AVR_GCC_VERSION 7.3.0)
-set(AVR_TOOLCHAIN_DIR "${PROJECT_CMAKE_DIR}/../.dependencies/avr-gcc-${AVR_GCC_VERSION}/")
-
+include("${PROJECT_CMAKE_DIR}/Utilities.cmake")
+get_dependency_directory("avr-gcc" AVR_TOOLCHAIN_DIR)
 include("${PROJECT_CMAKE_DIR}/AnyAvrGcc.cmake")