minstall: fix bug link #16693

Job	Run time
Arch Linux	20m 59s
CUDA (on Arch)	7m 51s
Fedora	19m 40s
Arch / PyPy	20m 1s
Ubuntu Rolling (gcc, g++)	19m 58s
Gentoo	25m 35s
Ubuntu Rolling (--unity=on -Ddefault_library=static, --no-unittests, gcc, g++)	13m 54s
OpenSUSE	16m 1s
Ubuntu Rolling (-Ddefault_library=both, --no-unittests, gcc, g++)	14m 32s
Ubuntu Bionic	15m 22s
Ubuntu Rolling (clang, clang++)	23m 23s
Ubuntu Rolling (--unity=on, --no-unittests, clang, clang++)	15m 32s
Ubuntu Rolling (--cross ubuntu-armhf.json --cross linux-mingw-w64-64bit.json, 0, gcc, g++)	13m 48s
Ubuntu Rolling (--cross ubuntu-armhf.json --cross linux-mingw-w64-64bit.json, --unity=on, gcc, g++)	14m 14s
	4h 0m 50s

Provide feedback