Enhance GCC compatibility of newlib integration

- Allow overriding GCC specific library location and search paths from
  CMake command line.
  This enables using GCC binaries which are unable to find libgcc.a.
- Enhance error handling and error messages.

Change-Id: Ie8ef9e1dd1bdece9f47595e14d3e3241b4621470
Signed-off-by: Gyorgy Szing <Gyorgy.Szing@arm.com>
1 file changed