Before patch:
% make cleandir -j12; script all.ts time make all -j12 MK_TESTS=no
...
objcopy --strip-debug --add-gnu-debuglink=libc.so.7.debug libc.so.7.full libc.so.7
111.55 real 280.00 user 39.12 sys
% wc -c all.ts
5118811 all.ts
%
Script done, output file is all.ts
After patch:
% make cleandir -j12; script all.ts time make all -j12 MK_TESTS=no
...
objcopy --strip-debug --add-gnu-debuglink=libc.so.7.debug libc.so.7.full libc.so.7
111.70 real 279.52 user 39.50 sys
Script done, output file is all.ts
% wc -c all.ts
4836944 all.ts
%
(and that savings is with just regular make output -- I'm not using -d at all)