gdal and thus PostGIS on Amazon Linux 2015.09 (and probably 2015.03 too)

(Related to:
http://www.postgresql.org/message-id/CAFE+72P35Z4TPTQz1mGMAfUgN70O3mAzg5geZ7JWbq_+4qjjSg@mail.gmail.com
)

I'm using the pgdg-95-ami201503.repo repository as a closest-match.
Perhaps this is a bad idea, but it would be very nice to have a repository
for the current Amazon Linux version (2015.09) though, if their release
pace holds up, there will soon be a 2016.03.

I notice that PostGIS cannot install on Amazon Linux. There are definitely
problems in "gdal":

$ sudo yum install gdal
[...]
Error: Package: gpsbabel-1.5.0-3.el6.x86_64 (epel)
Requires: libQtCore.so.4()(64bit)
Error: Package: gdal-1.9.2-7.rhel6.x86_64 (pgdg95)
Requires: libpoppler.so.5()(64bit)
Error: Package: gdal-libs-1.9.2-7.rhel6.x86_64 (pgdg95)
Requires: libpoppler.so.5()(64bit)

Both libpoppler and qt have been updated to newer versions. The libpoppler
version is courtesy of Amazon, as evidenced by the package name:

$ yum list 'poppler.x86_64'
Available Packages
poppler.x86_64
0.22.5-6.15.amzn1
amzn-main

qt4 is out, but qt5 is in, courtesy of EPEL:

$ yum list 'qt4*'
Error: No matching Packages to list

$ yum list 'qt5*qtbase*devel*64'
Available Packages
qt5-qtbase-devel.x86_64
5.5.1-11.el6 epel

If I remove the pgdg repository, I can install gdal. When done this way, it
has an eclectic mix of amazon and epel packages, though I do not know how
material the differences in those amazon packages are:

Installing:
gdal x86_64 1.7.3-15.el6
epel 3.0 M
Installing for dependencies:
cfitsio x86_64 3.240-3.el6
epel 498 k
compat-libtiff3 x86_64
3.9.4-10.13.amzn1 amzn-main
156 k
geos x86_64
3.4.2-1.4.amzn1 amzn-main
613 k
hdf5 x86_64
1.8.5.patch1-9.el6 epel
1.4 M
jasper-libs x86_64
1.900.1-16.9.amzn1 amzn-main
157 k
libdap x86_64 3.11.0-1.el6
epel 445 k
libgeotiff x86_64 1.2.5-6.el6
epel 574 k
libgfortran x86_64
4.8.3-9.109.amzn1 amzn-main
411 k
libquadmath x86_64
4.8.3-9.109.amzn1 amzn-main
234 k
librx x86_64 1.5-24.el6
epel 32 k
libtool-ltdl x86_64
2.4.2-20.4.8.3.31.amzn1 amzn-main
51 k
mysql51-libs x86_64
5.1.73-3.69.amzn1 amzn-main
1.4 M
netcdf x86_64 4.1.1-3.el6.5
epel 4.8 M
ogdi x86_64
3.2.0-0.14.beta2.el6 epel
230 k
proj x86_64 4.7.0-1.el6
epel 158 k
unixODBC x86_64
2.2.14-14.7.amzn1 amzn-main
483 k
xerces-c x86_64
3.0.1-0.20.1.el6 epel
862 k

The list of Amazon provided packages are at
https://aws.amazon.com/amazon-linux-ami/2015.09-packages/. It would seem
that even 2015.03 (which is specifically itemized as supported via PGDG)
that poppler is of a somewhat different flavor, as seen at
https://aws.amazon.com/amazon-linux-ami/2015.03-packages/ (indeed, they
would seem to have the same version, here.

What can we do to resolve this?