scons: allow use of current builds as default build settings Currently the --default= option only looks at the predefined build configs (in m5/build_opts), so you're limited to basing a new build config off of those (ALPHA_SE, etc.).  If you've already defined a non-standard build config and want to clone it or tweak it, you have to start from scratch.  This patch causes --default= to look first among the existing builds (in build/variables) before looking in build_opts so you can specify an existing non-standard build config as a starting point for a new config.
scons: allow use of current builds as default build settings
Currently the --default= option only looks at the predefined
build configs (in m5/build_opts), so you're limited to basing
a new build config off of those (ALPHA_SE, etc.).  If you've
already defined a non-standard build config and want to clone
it or tweak it, you have to start from scratch.  This patch
causes --default= to look first among the existing builds
(in build/variables) before looking in build_opts so you
can specify an existing non-standard build config as a
starting point for a new config.

yb-kim/gemV,aclifton/cpeg853-gem5,rallylee/gem5,zlfben/gem5,briancoutinho0905/2dsampling,zlfben/gem5,joerocklin/gem5,powerjg/gem5-ci-test,Weil0ng/gem5,aclifton/cpeg853-gem5,austinharris/gem5-riscv,Weil0ng/gem5,SanchayanMaity/gem5,cancro7/gem5,aclifton/cpeg853-gem5,sobercoder/gem5,rallylee/gem5,gedare/gem5,briancoutinho0905/2dsampling,markoshorro/gem5,KuroeKurose/gem5,SanchayanMaity/gem5,gem5/gem5,sobercoder/gem5,KuroeKurose/gem5,markoshorro/gem5,rjschof/gem5,zlfben/gem5,HwisooSo/gemV-update,cancro7/gem5,TUD-OS/gem5-dtu,gedare/gem5,qizenguf/MLC-STT,rjschof/gem5,SanchayanMaity/gem5,rallylee/gem5,kaiyuanl/gem5,powerjg/gem5-ci-test,TUD-OS/gem5-dtu,aclifton/cpeg853-gem5,briancoutinho0905/2dsampling,cancro7/gem5,rallylee/gem5,TUD-OS/gem5-dtu,KuroeKurose/gem5,KuroeKurose/gem5,KuroeKurose/gem5,gedare/gem5,rjschof/gem5,gedare/gem5,Weil0ng/gem5,zlfben/gem5,joerocklin/gem5,rallylee/gem5,qizenguf/MLC-STT,markoshorro/gem5,samueldotj/TeeRISC-Simulator,rjschof/gem5,HwisooSo/gemV-update,rjschof/gem5,rallylee/gem5,yb-kim/gemV,cancro7/gem5,sobercoder/gem5,samueldotj/TeeRISC-Simulator,aclifton/cpeg853-gem5,joerocklin/gem5,joerocklin/gem5,joerocklin/gem5,kaiyuanl/gem5,powerjg/gem5-ci-test,SanchayanMaity/gem5,austinharris/gem5-riscv,yb-kim/gemV,qizenguf/MLC-STT,sobercoder/gem5,gem5/gem5,powerjg/gem5-ci-test,HwisooSo/gemV-update,joerocklin/gem5,SanchayanMaity/gem5,rallylee/gem5,gem5/gem5,gedare/gem5,Weil0ng/gem5,briancoutinho0905/2dsampling,powerjg/gem5-ci-test,Weil0ng/gem5,joerocklin/gem5,yb-kim/gemV,gem5/gem5,samueldotj/TeeRISC-Simulator,samueldotj/TeeRISC-Simulator,briancoutinho0905/2dsampling,powerjg/gem5-ci-test,markoshorro/gem5,samueldotj/TeeRISC-Simulator,kaiyuanl/gem5,austinharris/gem5-riscv,cancro7/gem5,TUD-OS/gem5-dtu,qizenguf/MLC-STT,markoshorro/gem5,aclifton/cpeg853-gem5,gem5/gem5,kaiyuanl/gem5,austinharris/gem5-riscv,briancoutinho0905/2dsampling,joerocklin/gem5,kaiyuanl/gem5,samueldotj/TeeRISC-Simulator,samueldotj/TeeRISC-Simulator,cancro7/gem5,sobercoder/gem5,Weil0ng/gem5,austinharris/gem5-riscv,qizenguf/MLC-STT,gedare/gem5,sobercoder/gem5,gem5/gem5,rjschof/gem5,gedare/gem5,zlfben/gem5,HwisooSo/gemV-update,cancro7/gem5,SanchayanMaity/gem5,HwisooSo/gemV-update,HwisooSo/gemV-update,briancoutinho0905/2dsampling,rjschof/gem5,austinharris/gem5-riscv,zlfben/gem5,kaiyuanl/gem5,sobercoder/gem5,KuroeKurose/gem5,yb-kim/gemV,TUD-OS/gem5-dtu,yb-kim/gemV,zlfben/gem5,qizenguf/MLC-STT,qizenguf/MLC-STT,yb-kim/gemV,powerjg/gem5-ci-test,TUD-OS/gem5-dtu,markoshorro/gem5,yb-kim/gemV,austinharris/gem5-riscv,KuroeKurose/gem5,gem5/gem5,aclifton/cpeg853-gem5,SanchayanMaity/gem5,TUD-OS/gem5-dtu,HwisooSo/gemV-update,markoshorro/gem5,kaiyuanl/gem5,Weil0ng/gem5