[GRASS5] Using external PROJ with 5.3

[Paul Kelly]

Hello
Since Frank has now confirmed that PROJ bug number 368
http://bugzilla.remotesensing.org/show_bug.cgi?id=368
is in fact a feature and will be staying, I have put a workaround into the
5.3 modules that were affected (I still have to do ps.map in 5.7) that
uses the PROJ pj_latlong_from_proj() function to preserve the datum
information when converting to/from lat/long co-ordinates on the same
ellipsoid.

Just as a reminder, the problem was if you had a nadgrids line in your
PROJ_INFO file and were using external PROJ (not the internal GRASS PROJ),
a datum shift would be incorrectly applied and you would get the wrong
results when converting to/from latitude/longitude on the same ellipsoid
in modules such as r.sun, g.region -l, v.mkquads etc.

But now that this has been sorted out there is no reason not to use an
external PROJ (e.g. the latest PROJ.4.4.8) and I will make this
(--with-proj=yes) the default in the configure script for 5.3.0. I also think
the libproj shared library should probably be distributed with GRASS binaries,
as libgdal is now. Should prevent lots of spurious bug reports from people who
haven't installed libproj properly, as it will already be in their
LD_LIBRARY_PATH.

Paul