Fix some makeman issues.

• Don't bother looking up REVISION/BRANCH/etc from release/, or the CPUTYPE check, as these are not used for makeman and wastes time. The also invokes auto.obj.mk after I reverted auto.obj.mk ignoring -V in r291312.
• Don't modify CC or PATH when WITH_CCACHE_BUILD or WITH_META_MODE is enabled as it leads to bsd.compiler.mk errors.

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