Linker Problem: undefined reference to `__errno'
Actualy it does not matter whether “Use C math library” checked or unchecked, path to the library libm.a should be set in the “Library search path (-L)” and libraries clib (c) and mlib (m) should be set one after other.
See the attached picture.
The path to the library in my case
“E:\Design\Ac6\SystemWorkbench\plugins\fr.ac6.mcu.externaltools.arm-none.win32_1.7.0.201602121829\tools\compiler\arm-none-eabi\lib\thumb”
;){kind=link}