Title: Test multilib

Description:

Some architectures support different ISA variants, each backed a different
multilib in a same compiler. Selecting wrong multilib may have adverse
effects on performance, or sometime produce broken executables altogether
(for example, ARM Cortex-M requires thumb2 multilib and will be broken with
default ("arm") multilib or "thumb" multilib). This app is a smoke-test
for selecting non-wrong multilib - it uses operation(s) which guaranteedly
will call support routine(s) in libgcc and checks for expected result.

Sample failure output ("thumb" used on Cortex-M instead of "thumb2"):

***** USAGE FAULT *****
  Executing thread ID (thread): 0x200002a0
  Faulting instruction address:  0x00000000
  Illegal use of the EPSR
Fatal fault in essential task ! Spinning...