A tool builds with -j1 unless it sets HOST_BUILD_PARALLEL, and 45 of the
73 tools do not set it. These three gain the most from the job server on
a cold build of this tree:
erofs-utils 23.11 s -> 15.73 s
mtd-utils 11.70 s -> 6.42 s
cpio 8.46 s -> 3.56 s
Each one builds three times out of three with the job server, and each
build writes a tree that is identical to the one a serial build writes.
Signed-off-by: John Crispin <john@phrozen.org>
John Crispin
3d597977b6