This patch adds support for --prefix-alloc-sections, which adds a prefix
to every allocated section names.
It adds a prefix after renaming section names by --rename-section as GNU
objcopy does.
Fixes PR41266: https://bugs.llvm.org/show_bug.cgi?id=41266
Differential Revision: https://reviews.llvm.org/D60042
Patch by Seiya Nuta.
llvm-svn: 360233
James Henderson