libc/glibc: fix installed scripts

glibc installs some bash-scripts, but uses the path to the buildtool
bash as interpreter (on the shebang line). This is only a symlink to
the real bash, and thus is not available at runtime.

Fix that by assuming that bash on the target *will* be /bin/bash.

 reporter_name="Alexander BIGGA"

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

 reporter_comment=""