TS-1878: Add --as-needed to the linker flags
TS-1878: Add --as-needed to the linker flags

Normally the linker will link to every -llibrary mentioned on the
command line. This option causes it to skip libraries that it doesn't in
fact use any symbols from.

bryancall/trafficserver,duke8253/trafficserver,clearswift/trafficserver,rahmalik/trafficserver,PSUdaemon/trafficserver,chitianhao/trafficserver,davidbz/trafficserver,taoyunxing/trafficserver,chenglongwei/trafficserver,vmamidi/trafficserver,rahmalik/trafficserver,chenglongwei/trafficserver,rahmalik/trafficserver,davidbz/trafficserver,persiaAziz/trafficserver,reveller/trafficserver,pbchou/trafficserver,chenglongwei/trafficserver,PSUdaemon/trafficserver,bryancall/trafficserver,clearswift/trafficserver,davidbz/trafficserver,chitianhao/trafficserver,clearswift/trafficserver,persiaAziz/trafficserver,reveller/trafficserver,rahmalik/trafficserver,PSUdaemon/trafficserver,reveller/trafficserver,clearswift/trafficserver,duke8253/trafficserver,davidbz/trafficserver,duke8253/trafficserver,SolidWallOfCode/trafficserver,taoyunxing/trafficserver,rahmalik/trafficserver,taoyunxing/trafficserver,dyrock/trafficserver,chitianhao/trafficserver,PSUdaemon/trafficserver,rpufky/trafficserver,reveller/trafficserver,persiaAziz/trafficserver,SolidWallOfCode/trafficserver,SolidWallOfCode/trafficserver,rpufky/trafficserver,reveller/trafficserver,persiaAziz/trafficserver,chitianhao/trafficserver,PSUdaemon/trafficserver,dyrock/trafficserver,taoyunxing/trafficserver,clearswift/trafficserver,clearswift/trafficserver,clearswift/trafficserver,davidbz/trafficserver,chenglongwei/trafficserver,dyrock/trafficserver,chitianhao/trafficserver,chenglongwei/trafficserver,davidbz/trafficserver,bryancall/trafficserver,vmamidi/trafficserver,vmamidi/trafficserver,dyrock/trafficserver,rahmalik/trafficserver,PSUdaemon/trafficserver,dyrock/trafficserver,rpufky/trafficserver,reveller/trafficserver,pbchou/trafficserver,pbchou/trafficserver,rpufky/trafficserver,PSUdaemon/trafficserver,rahmalik/trafficserver,reveller/trafficserver,taoyunxing/trafficserver,rpufky/trafficserver,bryancall/trafficserver,taoyunxing/trafficserver,clearswift/trafficserver,duke8253/trafficserver,PSUdaemon/trafficserver,reveller/trafficserver,duke8253/trafficserver,chenglongwei/trafficserver,pbchou/trafficserver,taoyunxing/trafficserver,persiaAziz/trafficserver,persiaAziz/trafficserver,SolidWallOfCode/trafficserver,vmamidi/trafficserver,reveller/trafficserver,rpufky/trafficserver,SolidWallOfCode/trafficserver,dyrock/trafficserver,duke8253/trafficserver,vmamidi/trafficserver,rpufky/trafficserver,chenglongwei/trafficserver,pbchou/trafficserver,bryancall/trafficserver,SolidWallOfCode/trafficserver,rahmalik/trafficserver,chitianhao/trafficserver,SolidWallOfCode/trafficserver,taoyunxing/trafficserver,persiaAziz/trafficserver,bryancall/trafficserver,PSUdaemon/trafficserver,taoyunxing/trafficserver,pbchou/trafficserver,chenglongwei/trafficserver,rpufky/trafficserver,vmamidi/trafficserver,rahmalik/trafficserver,chitianhao/trafficserver,duke8253/trafficserver,clearswift/trafficserver,rpufky/trafficserver,dyrock/trafficserver,persiaAziz/trafficserver