Don't clean up pre-built docs if no docbook installed.
Fixes https://gitlab.freedesktop.org/fontconfig/fontconfig/issues/165
diff --git a/doc/Makefile.am b/doc/Makefile.am
index 2194ab7..2cb6410 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -33,11 +33,25 @@
confdir.sgml.in \
func.sgml \
$(NULL)
-MAINTAINERCLEANFILES = \
- $(DOC_FUNCS_SGML) \
+if USEDOCBOOK
+maintainerdoccleanfiles = \
+ $(NULL)
+cleandocfiles = \
+ $(BUILT_DOCS) \
+ $(NULL)
+else
+maintainerdoccleanfiles = \
+ $(BUILT_DOCS) \
+ $(NULL)
+cleandocfiles = \
+ $(NULL)
+endif
+MAINTAINERCLEANFILES = \
+ $(DOC_FUNCS_SGML) \
+ $(maintainerdoccleanfiles) \
$(NULL)
CLEANFILES = \
- $(BUILT_DOCS) \
+ $(cleandocfiles) \
$(LOCAL_SGML_FILES) \
confdir.sgml \
func.refs \
