Core: removed incorrect GCC 2.7 check.
Core: removed incorrect GCC 2.7 check.

It was broken since introduction (__GNU__ instead of __GNUC__) and did
nothing.  Moreover, GCC 2.7 is happy with the normal version of the code.

Reported by Joel Cunningham,
http://mailman.nginx.org/pipermail/nginx-devel/2016-March/007964.html.

hy0kl/nginx,hy0kl/nginx,hy0kl/nginx