Running `make buildall -j` in Chrome EC [1], the error below is shown.

```
$ git clone https://chromium.googlesource.com/chromiumos/platform/ec
$ make buildall -j # with futility from vboot in your path
[…]
======= building cr50
make --no-print-directory BOARD=cr50 V=
./util/getversion.sh: line 92: pushd: ../../third_party/tpm2: No such file or directory
./util/getversion.sh: line 101: popd: directory stack empty
./util/getversion.sh: line 92: pushd: ../../third_party/cryptoc: No such file or directory
./util/getversion.sh: line 101: popd: directory stack empty
make obj=/mnt/ec/build/cr50/tpm2 EMBEDDED_MODE=1 OBJ_PREFIX=Tpm2_ -C
make: option requires an argument -- 'C'
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.
  -O[TYPE], --output-sync[=TYPE]
                              Synchronize output of parallel jobs by TYPE.
  -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.
  --trace                     Print tracing information.
  -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.

This program built for x86_64-pc-linux-gnu
Report bugs to <bug-make@gnu.org>
board/cr50/build.mk:93: recipe for target 'build/cr50/tpm2/libtpm2.a' failed
make[2]: *** [build/cr50/tpm2/libtpm2.a] Error 2
```

It’d be great if that was checked, and the user/developer could get an informative message where to get these sources from.

[1] https://chromium.googlesource.com/chromiumos/platform/ec