update cmake build

examples/build_system/cmake/toolchain/common.cmake

@@ -0,0 +1,53 @@
+include(CMakePrintHelpers)
+
+# ----------------------------------------------------------------------------
+# Common
+# ----------------------------------------------------------------------------
+set(CMAKE_SYSTEM_NAME Generic)
+set_property(GLOBAL PROPERTY TARGET_SUPPORTS_SHARED_LIBS FALSE)
+
+# Look for includes and libraries only in the target system prefix.
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+
+# pass TOOLCHAIN_CPU to
+set(CMAKE_TRY_COMPILE_PLATFORM_VARIABLES CMAKE_SYSTEM_PROCESSOR)
+include(${CMAKE_CURRENT_LIST_DIR}/../cpu/${CMAKE_SYSTEM_PROCESSOR}.cmake)
+
+# ----------------------------------------------------------------------------
+# Compile flags
+# ----------------------------------------------------------------------------
+if (TOOLCHAIN STREQUAL "gcc")
+  list(APPEND TOOLCHAIN_COMMON_FLAGS
+    -fdata-sections
+    -ffunction-sections
+    -fsingle-precision-constant
+    -fno-strict-aliasing
+    )
+  list(APPEND TOOLCHAIN_EXE_LINKER_FLAGS
+    -Wl,--print-memory-usage
+    -Wl,--gc-sections
+    -Wl,--cref
+    )
+elseif (TOOLCHAIN STREQUAL "iar")
+  #list(APPEND TOOLCHAIN_COMMON_FLAGS)
+  list(APPEND TOOLCHAIN_EXE_LINKER_FLAGS
+    --diag_suppress=Li065
+    )
+elseif (TOOLCHAIN STREQUAL "clang")
+  message(FATAL_ERROR "Clang not supported")
+endif ()
+
+# join the toolchain flags into a single string
+list(JOIN TOOLCHAIN_COMMON_FLAGS " " TOOLCHAIN_COMMON_FLAGS)
+foreach (LANG IN ITEMS C CXX ASM)
+  set(CMAKE_${LANG}_FLAGS_INIT ${TOOLCHAIN_COMMON_FLAGS})
+  # optimization flags for LOG, LOGGER ?
+  #set(CMAKE_${LANG}_FLAGS_RELEASE_INIT "-Os")
+  #set(CMAKE_${LANG}_FLAGS_DEBUG_INIT "-O0")
+endforeach ()
+
+# Linker
+list(JOIN TOOLCHAIN_EXE_LINKER_FLAGS " " CMAKE_EXE_LINKER_FLAGS_INIT)