[Ohrrpgce] SVN: teeemcee/11372 ohrhelp files weren't found when installed system-wide on Linux

[subversion at HamsterRepublic.com]

teeemcee
2019-11-06 17:21:31 -0800 (Wed, 06 Nov 2019)
353
ohrhelp files weren't found when installed system-wide on Linux

I broke this in r10708 (a year ago) when removing the DATAFILES define,
which also broke searching for data/, but I fixed that problem in r10885.

Note that when installed in a read-only location, the cwd is changed from
exepath, but my change to get_help_dir assumed they were identical.
---
U   wip/common.rbas