b=1033122 be consistent about speex_resampler symbol visibility r=khuey

When "speex/speex_resampler.h" was included, another exported header (in
dist/include) would find the speex/speex_resampler.h in dist/include before
dist/system_wrappers.  Visibility of undefined symbols depended on the order
of includes.

This patch changes includes to <speex/speex_resampler.h> so that
WRAP_SYSTEM_INCLUDES works as expected but removes the wrapper when not using
GKMEDIAS_SHARED_LIBRARY.

--HG--
extra : rebase_source : 93ca1dbdd6b489647624326e78539f44c60d0b34
crashtest for bug 944851

based on testcase by Jesse Ruderman <jruderman@gmail.com>

--HG--
extra : rebase_source : f9bbe6e23afac15180a91e7c6d276483e4320d3a
crashtest for bug 966636

derived from testcase by Atte Kettunen <attekett@gmail.com>

--HG--
extra : rebase_source : 8ec0f239e118d92e04b368490c49dd045bfc5ca5
crashtest for bug 990794

--HG--
extra : rebase_source : 8d6ff4e6fdfe51e32cca22ecaeb84b59c18ad4ae