tree b2a6e88cb99912575a5a2f0820c460a2d54b2a99
parent 89c40005bfceadb4163bd16b7464b3c2ce740daf
author Alex Stewart <alexs.mac@gmail.com> 1443476622 +0100
committer Alex Stewart <alexs.mac@gmail.com> 1444067651 +0100

Remove link-time optimisation (LTO).

- On GCC 4.9+ although GCC supports LTO, it requires use of the
  non-default gcc-ar & gcc-ranlib.  Whilst we can ensure Ceres is
  compiled with these, doing so with GCC 4.9 causes multiple definition
  linker errors of static ints inside Eigen when compiling the tests
  and examples when they are not also built with LTO.
- On OS X (Xcode 6 & 7) after the latest update to gtest, if LTO
  is used when compiling the tests (& examples), two tests fail
  due to typeinfo::operator== (things are fine if only Ceres itself is
  compiled with LTO).
- This patch disables LTO for all compilers. It should be revisited when
  the performance is more stable across our supported compilers.

Change-Id: I17b52957faefbdeff0aa40846dc9b342db1b02e3