As discussed in
id:8cc9dd580ad672527e12f43706f9803b2c8e99d8.1405220724.git.wking@tremily.us,
execfile is unavailable in python3.
The approach of this commit avoids modifying the python module path,
which is arguably preferable since it avoids potentially accidentally
importing a module from the wrong place.
Avoid:
$ make HAVE_SPHINX=0 HAVE_RST2MAN=1 build-man
python ./doc/prerst2man.py ./doc doc/_build/man
Traceback (most recent call last):
File "./doc/prerst2man.py", line 65, in <module>
os.system('set -x; rst2man {0} {1}/{2}.{3}'
NameError: name 'os' is not defined
make: *** [doc/_build/man/man1/notmuch.1] Error 1
by using system directly. We don't need the 'os.' namespacing,
because the function was imported with:
from os import makedirs, system
