race condition when making with dependency cloning

[midnightveil]

julia@eta-carinae ~/t/p/l/e/fileio (main)> make MICROKIT_BOARD=qemu_virt_riscv64 -j8 qemu
mkdir -p /home/julia/ts/pistisv_lionsos_demo/lionsos/examples/fileio/build
echo "export LIONSOS ?= /home/julia/ts/pistisv_lionsos_demo/lionsos" > /home/julia/ts/pistisv_lionsos_demo/lionsos/examples/fileio/build/Makefile
echo "export FILEIO_DIR ?= /home/julia/ts/pistisv_lionsos_demo/lionsos/examples/fileio" >> /home/julia/ts/pistisv_lionsos_demo/lionsos/examples/fileio/build/Makefile
echo "export BUILD_DIR := /home/julia/ts/pistisv_lionsos_demo/lionsos/examples/fileio/build" >> /home/julia/ts/pistisv_lionsos_demo/lionsos/examples/fileio/build/Makefile
echo "export MICROKIT_BOARD ?= qemu_virt_riscv64" >> /home/julia/ts/pistisv_lionsos_demo/lionsos/examples/fileio/build/Makefile
echo "export MICROKIT_SDK ?= /nix/store/hks8382gbahcpv384fhw4sj0f1ly9m69-source" >> /home/julia/ts/pistisv_lionsos_demo/lionsos/examples/fileio/build/Makefile
echo "export MICROKIT_CONFIG ?= debug" >> /home/julia/ts/pistisv_lionsos_demo/lionsos/examples/fileio/build/Makefile
cat fileio.mk >> /home/julia/ts/pistisv_lionsos_demo/lionsos/examples/fileio/build/Makefile
make -C /home/julia/ts/pistisv_lionsos_demo/lionsos/examples/fileio/build MICROKIT_SDK=/nix/store/hks8382gbahcpv384fhw4sj0f1ly9m69-source qemu
make[1]: Entering directory '/home/julia/ts/pistisv_lionsos_demo/lionsos/examples/fileio/build'
cd /home/julia/ts/pistisv_lionsos_demo/lionsos; git submodule update --init dep/sddf
Makefile:58: /home/julia/ts/pistisv_lionsos_demo/lionsos/dep/sddf/util/util.mk: No such file or directory
make[1]: *** No rule to make target '/home/julia/ts/pistisv_lionsos_demo/lionsos/dep/sddf/util/util.mk'.  Stop.
make[1]: *** Waiting for unfinished jobs....
Submodule 'sddf' (https://github.com/au-ts/sddf.git) registered for path 'dep/sddf'
Cloning into '/home/julia/ts/pistisv_lionsos_demo/lionsos/dep/sddf'...
Submodule path 'dep/sddf': checked out 'b0e86b1d5082ec8680585ad3429a8a519efa57ff'
make[1]: Leaving directory '/home/julia/ts/pistisv_lionsos_demo/lionsos/examples/fileio/build'
make: *** [Makefile:24: qemu] Error 2
julia@eta-carinae ~/t/p/l/e/fileio (main

The include of util.mk happens before the git submodule is cloned, which errors.