check flags:    
building check-recursive
Making check in lib
make[1]: Entering directory `/tmp/nix-build-s15izg8dqm5qbj9w9q36al62xjb6d144-config-support.drv-0/config-support-1.4/lib'
make[1]: Nothing to be done for `check'.
make[1]: Leaving directory `/tmp/nix-build-s15izg8dqm5qbj9w9q36al62xjb6d144-config-support.drv-0/config-support-1.4/lib'
make[1]: Entering directory `/tmp/nix-build-s15izg8dqm5qbj9w9q36al62xjb6d144-config-support.drv-0/config-support-1.4'
make[1]: Nothing to be done for `check-am'.
make[1]: Leaving directory `/tmp/nix-build-s15izg8dqm5qbj9w9q36al62xjb6d144-config-support.drv-0/config-support-1.4'