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="Ioannis E. VENETIS"

reporter_url="http://sourceware.org/ml/crossgcc/2008-06/msg00017.html"

reporter_comment=""