Steady improvement in RHEL support

[Jason Bacon <outpaddling%yahoo.com@localhost>]

Package counts from full pbulk builds on CentOS 6 & 7:

www/pkgsrc/packages/sharedapps/pkg-2017Q1/RHEL6/All    15631
www/pkgsrc/packages/sharedapps/pkg-2017Q2/RHEL6/All    16297
www/pkgsrc/packages/sharedapps/pkg-2017Q3/RHEL6/All    16461
www/pkgsrc/packages/sharedapps/pkg-2017Q4/RHEL6/All    16525
www/pkgsrc/packages/sharedapps/pkg-2018Q1/RHEL6/All    17303
www/pkgsrc/packages/usr/pkg/RHEL6/All    17378

www/pkgsrc/packages/sharedapps/pkg-2017Q1/RHEL7/All    15702
www/pkgsrc/packages/sharedapps/pkg-2017Q2/RHEL7/All    16043
www/pkgsrc/packages/sharedapps/pkg-2017Q3/RHEL7/All    16414
www/pkgsrc/packages/sharedapps/pkg-2017Q4/RHEL7/All    16870
www/pkgsrc/packages/sharedapps/pkg-2018Q1/RHEL7/All    17552
www/pkgsrc/packages/usr/pkg/RHEL7/All    17809

Builds of 2017Q4 and later use gcc5 for everything.

2017Q[23] use gcc48.

The /usr/pkg snapshot is a recent -current snapshot that also uses 
pkgsrc binutils in gcc builds, as RHEL's "as" does not keep up with 
gcc's support for new instruction sets.

Packages and pbulk reports available here:

http://mirror1.hpc.uwm.edu/
http://mirror2.hpc.uwm.edu/