libc/newlib: cleanup the build and finish steps

build step:
- ./configure
- remove glibc-specific options
- pass the target CFLAGS in the correct variable
- make:
- build in //

finish step:
- print proper message in finish step

 reporter_name="Alexander BIGGA"

 reporter_url="http://sourceware.org/ml/crossgcc/2008-07/msg00000.html"

 reporter_comment=""