のように「-j」オプションで、make が早くなるだなんて、知りませんでした。
$ make --help
Usage: make [options] [target] ...
Options:
-b, -m Ignored for compatibility.
-B, --always-make Unconditionally make all targets.
-C DIRECTORY, --directory=DIRECTORY
Change to DIRECTORY before doing anything.
-d Print lots of debugging information.
--debug[=FLAGS] Print various types of debugging information.
-e, --environment-overrides
Environment variables override makefiles.
--eval=STRING Evaluate STRING as a makefile statement.
-f FILE, --file=FILE, --makefile=FILE
Read FILE as a makefile.
-h, --help Print this message and exit.
-i, --ignore-errors Ignore errors from recipes.
-I DIRECTORY, --include-dir=DIRECTORY
Search DIRECTORY for included makefiles.
-j [N], --jobs[=N] Allow N jobs at once; infinite jobs with no arg.
-k, --keep-going Keep going when some targets can't be made.
-l [N], --load-average[=N], --max-load[=N]
Don't start multiple jobs unless load is below N.
-L, --check-symlink-times Use the latest mtime between symlinks and target.
-n, --just-print, --dry-run, --recon
Don't actually run any recipe; just print them.
-o FILE, --old-file=FILE, --assume-old=FILE
Consider FILE to be very old and don't remake it.
-p, --print-data-base Print make's internal database.
-q, --question Run no recipe; exit status says if up to date.
-r, --no-builtin-rules Disable the built-in implicit rules.
-R, --no-builtin-variables Disable the built-in variable settings.
-s, --silent, --quiet Don't echo recipes.
-S, --no-keep-going, --stop
Turns off -k.
-t, --touch Touch targets instead of remaking them.
-v, --version Print the version number of make and exit.
-w, --print-directory Print the current directory.
--no-print-directory Turn off -w, even if it was turned on implicitly.
-W FILE, --what-if=FILE, --new-file=FILE, --assume-new=FILE
Consider FILE to be infinitely new.
--warn-undefined-variables Warn when an undefined variable is referenced.
--warn-undefined-functions Warn when an undefined user function is called.
This program built for x86_64-redhat-linux-gnu
Report bugs to <bug-make@gnu.org>
