cc/gcc: Update core_prefix_dir to prefix.
core_prefix_dir is not defined. It should be prefix.
Signed-off-by: Zhenqiang Chen <zhenqiang.chen@linaro.org>
1 reporter_name="Yann E. MORIN"
2 reporter_url="http://ymorin.is-a-geek.org/projects/crosstool"
3 reporter_comment="EXPERIMENTAL MIPS-64 n64 toolchain."