LTO doesn't work with FATE

[Timothy Gu]

See ​http://fate.ffmpeg.org/log.cgi?time=20150407222218&log=test&slot=x86_64-archlinux-gcc-lto

A lot of undefined references, like:

/tmp/ccCjxl2i.ltrans0.ltrans.o: In function `main':
<artificial>:(.text.startup+0x56): undefined reference to `avpriv_open'
<artificial>:(.text.startup+0x92): undefined reference to `avpriv_open'
<artificial>:(.text.startup+0xc5): undefined reference to `av_sha_size'
<artificial>:(.text.startup+0x222): undefined reference to `av_sha_init'
<artificial>:(.text.startup+0x236): undefined reference to `av_sha_update'
<artificial>:(.text.startup+0x243): undefined reference to `av_sha_final'
<artificial>:(.text.startup+0x27e): undefined reference to `av_log'
collect2: error: ld returned 1 exit status
/home/ux/fate/ffmpeg/library.mak:110: recipe for target 'libavutil/random_seed-test' failed
make: *** [libavutil/random_seed-test] Error 1

[Carl Eugen Hoyos]

This works fine here with gcc 4.9.1, gcc 5.1.0 and a recent icc version.
The fate client is missing --ar=gcc-ar and --ranlib=true or --ranlib=gcc-ranlib (I didn't know about gcc-ar and gcc-ranlib when I suggested Clément to add the lto fate client). Default (old) ranlib damages the lto archives made with gcc-ar, icc only needs --ar=xiar.