MFH: r469300 r469389
Add clang60 support
Update howto
- 11.0+ base can just use WITH_CCACHE_BUILD=yes [1]
- Remove older advise for libtool which is no longer needed
- No need for clang unused argument hack anymore
PR: 222765 [1]
Submitted by: pete@nomadlogic.org [1] (based on)
Approved by: portmgr (implicit)