Mark some functions as cold

Add Q_DECL_COLD_FUNCTION (__attribute__((cold))) to tell the compiler
that the following functions are not usually executed in normal programs:

- qWarning/qCritical/qFatal
- qTerminate
- assertion failure
- qBadAlloc

The effect of the attribute is that

1. These functions get put into their own section, .text.unlikely,
   and will be optimized for size, not speed.
2. Conditions that lead to one of these functions are automatically
   marked as unlikely (something we have done manually in the past)
3. (anecdotal) the compiler is less likely to inline these functions

Text size effect of this change over all of QtBase: ~27KiB text size
saved, of which 11KiB in QtCore alone.

Change-Id: If308d4a4b9ff8f7934316c54b161a78ebe3f4205
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

0 files changed, 0 insertions, 0 deletions