Make COMPILE_DOUBLE magic actually work.

Make COMPILE_DOUBLE magic actually work.

The build system has some special magic to ensure that if Asterisk is built
with --enable-dev-mode *and* DONT_OPTIMIZE, that all the source is still compiled
with the optimizer enabled (even though the result will be thrown away), because
the compiler is able to find a great deal of coding errors and bugs as a result
of running its optimizers. Unfortunately at some point this mode got broken,
and the 'throwaway' compile of the code was no longer done with the optimizer
enabled. This patch corrects that problem.

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@357212 65c4cc65-6c06-0410-ace0-fbb531ad65f3