[Opus] Update to v1.2.1

third_party/opus/src/doc/Doxyfile.in

 # Doxyfile 1.8.10
 
 # This file describes the settings to be used by the documentation system
 # doxygen (www.doxygen.org) for a project.
 #
 # All text after a double hash (##) is considered a comment and is placed in
 # front of the TAG it is preceding.
 #
 # All text after a single hash (#) is considered a comment and will be ignored.
 # The format is:
@@ skipping 300 matching lines @@
 # name=definition (no spaces). If the definition and the "=" are omitted, "=1"
 # is assumed. To prevent a macro definition from being undefined via #undef or
 # recursively expanded use the := operator instead of the = operator.
 # This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
 
 PREDEFINED             = OPUS_EXPORT= \
                          OPUS_CUSTOM_EXPORT= \
                          OPUS_CUSTOM_EXPORT_STATIC= \
                          OPUS_WARN_UNUSED_RESULT= \
                          OPUS_ARG_NONNULL(_x)=
+
+#---------------------------------------------------------------------------
+# Configuration options related to the dot tool
+#---------------------------------------------------------------------------
+
+# If you set the HAVE_DOT tag to YES then doxygen will assume the dot tool is
+# available from the path. This tool is part of Graphviz (see:
+# http://www.graphviz.org/), a graph visualization toolkit from AT&T and Lucent
+# Bell Labs.
+
+# Debian defaults to YES here, while Fedora and Homebrew default to NO.
+# So we set this based on whether the graphviz package is available at
+# configure time.
+#
+HAVE_DOT = @HAVE_DOT@