title: CMake separate flags for Assembler
body: <p>I am trying to cross-compile a project for an ARM target, using the GCC cross compiler. I created  a target and set things like ABI flags (-mcpu, -mfpu etc.) with target_compile_options() and defines which target_compile_definitions(). However, I now have the issue that these flags are passed to the assembler call as well. Is there a way to use separate assembler flags for the assembler call?</p>
  <pre><code>[ 65%] Building CXX object CMakeFiles/fsfw_example.dir/bsp_stm32/main.cpp.obj
  arm-none-eabi-g++ -DSTM32H743xx -DUSE_HAL_DRIVER 
  -Ibla\bla &lt;more includes here&gt; -g -specs=nosys.specs 
  -specs=nano.specs -mcpu=cortex-m7 -mfpu=fpv5-d16 -mfloat-abi=hard 
  -mthumb -ffunction-sections -fdata-sections 
  -std=gnu++11 -o CMakeFiles\fsfw_example.dir\bsp_stm32\main.cpp.obj 
  -c C:\Users\Robin\Documents\FSFW\fsfw_example\bsp_stm32\main.cpp
  
  [ 66%] Building ASM object CMakeFiles/fsfw_example.dir/bsp_stm32/startup_stm32h743xx.s.obj
      arm-none-eabi-as -DSTM32H743xx -DUSE_HAL_DRIVER -Ibla\bla &lt;more includes here&gt; 
  -mcpu=cortex-m7;-mfpu=fpv5-d16;-mfloat-abi=hard;-mthumb -g -specs=nosys.specs 
  -specs=nano.specs -mcpu=cortex-m7 -mfpu=fpv5-d16 -mfloat-abi=hard -mthumb 
  -ffunction-sections -fdata-sections -o CMakeFiles\fsfw_example.dir\bsp_stm32\startup_stm32h743xx.s.obj 
  -c C:\Users\Robin\Documents\FSFW\fsfw_example\bsp_stm32\startup_stm32h743xx.s
  </code></pre>
  <p>Problem is: The arm-none-eabi-as is not able to process the defines. Is it possible to remove them for the assembler compilation process specifically?
  I also tried to set source specific flags but that does not appear to work, the target compile options/defines appear to have priority.</p>
  <p>Kind Regards
  Robin</p>