build: make graphviz optional for building documentation
Change-Id: Icff993cccc675c95cd6f671cd217c74d7768fac9
diff --git a/docs/doxygen.conf.in b/docs/doxygen.conf.in
index 8e31136..d70ac1c 100644
--- a/docs/doxygen.conf.in
+++ b/docs/doxygen.conf.in
@@ -230,12 +230,6 @@
ALIASES =
-# This tag can be used to specify a number of word-keyword mappings (TCL only).
-# A mapping has the form "name=value". For example adding "class=itcl::class"
-# will allow you to use the command class in the itcl::class meaning.
-
-TCL_SUBST =
-
# Set the OPTIMIZE_OUTPUT_FOR_C tag to YES if your project consists of C sources
# only. Doxygen will then generate output that is more tailored for C. For
# instance, some of the names that are used will be different. The list of all
@@ -2161,7 +2155,7 @@
# set to NO
# The default value is: YES.
-HAVE_DOT = YES
+HAVE_DOT = @HAVE_DOT@
# The DOT_NUM_THREADS specifies the number of dot invocations doxygen is allowed
# to run in parallel. When set to 0 doxygen will base this on the number of