Remove the -falign-stack option from ICC's mkspec.

Remove the -falign-stack option from ICC's mkspec.

This option was necessary in early ICC 12 releases because of a
difference in interpreting the ABI requirements with GCC. According to
ICC devs, GCC changed the ABI on its own to require 16-byte-aligned
stacks on i386.

It looks like this option has been the default in later ICC 12
releases. At least 12.1 update 5 has it by default. ICC 13 does not
have the option anymore but accepts it silently for backwards
compatibility.

Change-Id: Id8bb4c250718eef2f02dc97bd47a0efd95b272fc
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>