tests: avoid test failures when PATH contains an unsearchable directory
tests: do not fail on read-only root file system
maint: cfg.mk: remove factored-out ftp host/dir definitions
maint: correct comments in test scripts
maint: don't list "warnings" module explicitly
build: update gnulib submodule to latest
maint: move xfreopen module to gnulib
tests: avoid spurious failures due to insecure directory in PATH
build: "make stable" emitted an invalid gnupload command
post-release administrivia