Update to the 20140209 snapshot of GCC 4.9.0.
Configure with --enable-gnu-indirect-function to enable the "ifunc"
attribute, a GCC extension. 
Remove the man7 pages, which we are not packaging, from the staging area
to silence some warnings some are concerned about (needlessly ;-). 
No longer run ccache-update-links as part of post-install which, in
the world of staging, no longer is what it used to be. Rely on the
existing @exec and @unexec in pkg-plist instead. 
Submitted by: jmg , miwi 
Discussed with: kib , antoine