Bug#724526: ardour3: FTBFS on non-x86: xmmintrin.h: No such file or directory

[Aaron M. Ucko]

Source: ardour3
Version: 3.4~dfsg-2
Severity: important

Builds of ardour3 on non-x86 architectures have been failing because
they still try to use x86 SSE extensions:

  ../libs/ardour/sse_functions_xmm.cc:21:23: fatal error: xmmintrin.h: No such file or directory

I see that these builds are still running with -DBUILD_SSE_OPTIMIZATIONS
for some reason; can you perhaps conditionalize this flag's use?  (I'd
suggest doing without it and the corresponding -m* flags on i386 as well
to yield more portable binaries.)  At any rate, please do take a look.

Thanks!