I have read the compilers.conf manual page and want to try instructions from there: $ fetch http://leaf.dragonflybsd.org/~swildner/world_clang.diff world_clang.diff 100% of 1555 B 868 kBps $ patch -p1 <world_clang.diff ... Patching file lib/csu/i386/Makefile.csu using Plan A... Hunk #1 failed at 1. 1 out of 1 hunks failed--saving rejects to lib/csu/i386/Makefile.csu.rej ...