From: John <jpsinthemix@verizon.net>
Date: Wed, 4 Jun 2014 15:45:42 +0000 (+0200)
Subject: build-sys: accommodate gcc-4.9.0 link-time optimization (LTO) changes
X-Git-Tag: v214~81
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;ds=sidebyside;h=235c6e628199221b7885f159367614b7105547cf;hp=235c6e628199221b7885f159367614b7105547cf;p=elogind.git

build-sys: accommodate gcc-4.9.0 link-time optimization (LTO) changes

systemd fails to build (symbols not found/resolved during cgls link step)
under gcc-4.9.0 due to link-time optimization (lto) changes, in particular
from gcc-4.9.0/NEWS:

  + When using a linker plugin, compiling with the -flto option
    now generates slim objects files (.o) which only contain
    intermediate language representation for LTO. Use
    -ffat-lto-objects to create files which contain additionally
    the object code. To generate static libraries suitable for LTO
    processing, use gcc-ar and gcc-ranlib; to list symbols from a
    slim object file use gcc-nm. (Requires that ar, ranlib and nm
    have been compiled with plugin support.)

Both -flto and -ffat-lto-objects are now needed when building and linking
against static libs w/LTO.
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