Remove the obsolete LIBOPUS_SUFFIX define.

As best we recall, this was used to version the
library filename during rapid development. It's
no longer needed now that the bitstream is frozen
and isn't hooked up to anything in the build system.

configure.ac

@@ -37,8 +37,6 @@ AC_DEFINE_UNQUOTED(OPUS_MICRO_VERSION, ${OPUS_MICRO_VERSION}, [Version micro])
 AC_DEFINE_UNQUOTED(OPUS_EXTRA_VERSION, "${OPUS_EXTRA_VERSION}", [Version extra])
 
 # For libtool.
-LIBOPUS_SUFFIX=0
-
 OPUS_LT_CURRENT=0
 OPUS_LT_REVISION=0
 OPUS_LT_AGE=0
@@ -46,7 +44,6 @@ OPUS_LT_AGE=0
 AC_SUBST(OPUS_LT_CURRENT)
 AC_SUBST(OPUS_LT_REVISION)
 AC_SUBST(OPUS_LT_AGE)
-AC_SUBST(LIBOPUS_SUFFIX)
 
 AM_INIT_AUTOMAKE($PACKAGE, $VERSION, no-define)
 AM_MAINTAINER_MODE