IPO: gcc 4.7 is required for -fno-fat-lto-objects
Merge topic 'gcc-ipo' into next

58d284d0 IPO: gcc 4.7 is required for -fno-fat-lto-objects
IPO: implemented INTERPROCEDURAL_OPTIMIZATION for gcc (-flto)

Using the IPO specific rule variables in the Ninja generator should
fix intel IPO as well.
Merge topic 'gcc-ipo' into next

bc37c2d8 IPO: implemented INTERPROCEDURAL_OPTIMIZATION for gcc (-flto)