build: support CentOS Stream 9, make graphviz optional
Change-Id: I5c0d824720f9f701ee2a88774e661c7472baea88
diff --git a/docs/doxygen.conf.in b/docs/doxygen.conf.in
index 7a74246..da86688 100644
--- a/docs/doxygen.conf.in
+++ b/docs/doxygen.conf.in
@@ -68,7 +68,7 @@
# performance problems for the file system.
# The default value is: NO.
-CREATE_SUBDIRS = YES
+CREATE_SUBDIRS = NO
# If the ALLOW_UNICODE_NAMES tag is set to YES, doxygen will allow non-ASCII
# characters to appear in the names of generated files. If set to NO, non-ASCII
@@ -2117,7 +2117,7 @@
# 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