https://bugs.gentoo.org/310157
--- fontconfig-2.10.2-orig/configure.ac
+++ fontconfig-2.10.2/configure.ac
@@ -570,7 +570,11 @@ AC_SUBST(XMLDIR)
 # Let people not build/install docs if they don't have docbook
 #
 
-AC_CHECK_PROG(HASDOCBOOK, docbook2html, yes, no)
+AC_ARG_ENABLE(docbook,           [  --disable-docbook                Don't build documentation],,)
+
+if test x$enable_docbook != xno; then
+	AC_CHECK_PROG(HASDOCBOOK, docbook2html, yes, no)
+fi
 
 AM_CONDITIONAL(USEDOCBOOK, test "x$HASDOCBOOK" = xyes)