I'm not 100% sure if this is the right thing to do, but at least
it seems to be worth discussing. This patch adds a new command line
flag, --fast, to the linker. That flag disables costly but optional
features so that the linker produces semantically correct (but larger)
output quickly. Currently it only disables section merging.
This flag is not intended to be used for final production linking.
It is intended to be used in compile-link-test cycle.
Time to link clang with debug info is about 2x faster with the flag.
Head: 13.24 seconds Output size: 1227189664 bytes With this patch: 7.41 seconds Output size: 2490281784 bytes