fix cmake build

examples/cmake/toolchain/set_flags.cmake

@@ -0,0 +1,20 @@
+include(CMakePrintHelpers)
+foreach(LANG IN ITEMS C CXX ASM)
+    # join the toolchain flags into a single string
+    list(APPEND TOOLCHAIN_${LANG}_FLAGS ${TOOLCHAIN_COMMON_FLAGS})
+    list(JOIN TOOLCHAIN_${LANG}_FLAGS " " TOOLCHAIN_${LANG}_FLAGS)
+    set(CMAKE_${LANG}_FLAGS_INIT "${TOOLCHAIN_${LANG}_FLAGS}")
+
+    #cmake_print_variables(CMAKE_${LANG}_FLAGS_INIT)
+
+    # optimization flags
+    set(CMAKE_${LANG}_FLAGS_DEBUG_INIT "-Og")
+endforeach()
+
+# try_compile is cmake test compiling its own example,
+# pass -nostdlib to skip stdlib linking
+get_property(IS_IN_TRY_COMPILE GLOBAL PROPERTY IN_TRY_COMPILE)
+if(IS_IN_TRY_COMPILE)
+    set(CMAKE_C_LINK_FLAGS "${CMAKE_C_LINK_FLAGS} -nostdlib")
+    set(CMAKE_CXX_LINK_FLAGS "${CMAKE_CXX_LINK_FLAGS} -nostdlib")
+endif()