Stdune.Env_path
SourceHandle the PATH
environment variable.
cons env ~dir
adds dir
to the start of the PATH variable in env
extend_env_concat_path a b
adds all variables from b
to a
overwriting any existing values of those variables in a
except for PATH which is set to the concatenation of the PATH variables from a
and b
with the PATH entries from b
preceding the PATH entries from a