GCC-5.0 now available in DragonFly master.

[Matthew Dillon]

    We are happy to announce that John Marino has finished integrating gcc-5.0
    into the DragonFlyBSD base system!  gcc-5.0 can be tested by setting
    your CCVER to 'gcc50'.  Note that you would set your CCVER to 'gcc5' for
    the lang/gcc5 dport, which also works.

    DragonFly has a two-compilers-in-base policy, controlled by the CCVER
    environment variable.  We have dropped gcc-4.4 and added gcc-5.0.  We now
    have gcc-4.7.4 and gcc-5.0 in base, with gcc-4.7.4 being the
    current default.

    gcc-5.0 is considered experimental and will not become the default for
    some time.  Now that it is in base more developers can work on validating
    it for our world and kernel builds.

    --

    The gcc-5.x build is quite a bit larger than the gcc-4.x build due to
    being more dependant on C++, so buildworld will take longer.  John has
    mitigated the issue on multi-core systems by significantly improving
    build concurrency (reducing buildworld bottlenecks that leave cores
    idle).  Our test build numbers for buildworld between -release and master
    are as follows:

	monster -j 48 build (48-core 1.9 GHz opteron 6168 x 4):
	    release     929.08 real      6338.02 user      4095.37 sys
	    master      945.65 real      7946.20 user      4568.24 sys

	blade -j 12 build (E3-1240v3 w/8-threads):
	    release     771.73 real      3145.34 user      1223.97 sys
	    master      906.42 real      4056.47 user      1394.64 sys

    So the build in this configuration on a recent cpu like haswell takes
    911 seconds more cpu time but concurrency has improved by 776 seconds
    so the real-time difference is only 135 seconds slower.

    On machines with fewer cores the real-time build time will be longer,
    significantly longer on single-core systems, but we'll just have to live
    with it.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>