Bug 811544 - Build fixed-point opus on arm. r=ted

Enable MOZ_OPUS_FIXED inside the opus makefile if
MOZ_SAMPLE_TYPE_FLOAT32 is not defined. This is the
general proxy for floating point audio support in
other areas of the code.

We could have defined MOZ_OPUS_FIXED directly in
the configure script (and still could) but I liked
this better.

media/libopus/Makefile.in

@@ -68,6 +68,10 @@ CSRCS = \
   $(notdir $(OPUS_SOURCES)) \
   $(NULL)
 
+ifndef MOZ_SAMPLE_TYPE_FLOAT32
+  MOZ_OPUS_FIXED = 1
+endif
+
 ifdef MOZ_OPUS_FIXED
 DEFINES += -DFIXED_POINT=1 -DDISABLE_FLOAT_API
 LOCAL_INCLUDES += -I$(srcdir)/silk/fixed