plantuml now also works for old doxygen versions

scripts/ax_init_standard_project.m4

@@ -573,7 +573,11 @@ AC_DEFUN([AX_USE_DOXYGEN], [
   AX_ADD_MAKEFILE_TARGET_DEP([.PHONY], [pdf gen-uml-images], [doc/makefile.in])
   test -f doc/makefile.in && cat >> doc/makefile.in <<EOF
 #### Begin: Appended by $0
-doc: doxyfile @NEED_PLANTUML_TRUE@ den-uml-images
+doc: doxyfile @NEED_PLANTUML_TRUE@ gen-uml-images
+	@NEED_PLANTUML_TRUE@ doxyadd() { grep -q "\$\$[1] += \$\$[2]" doxyfile || sed -i '/^'"\$\$[1]"' *=/a'"\$\$[1]"' += '"\$\$[2]" doxyfile; }; \\
+	@NEED_PLANTUML_TRUE@ doxyadd ALIASES '"startuml{1}=@image html \\\\1\\\\n@image latex \\\\1\\\\n\\\\if DontIgnorePlantUMLCode"'; \\
+	@NEED_PLANTUML_TRUE@ doxyadd ALIASES '"enduml=\\\\endif"'; \\
+	@NEED_PLANTUML_TRUE@ doxyadd IMAGE_PATH '"gen-uml-images"';
 	doxygen doxyfile
 @PEDANTIC_TRUE@	test \! -s doxygen.errors
 

scripts/bootstrap.sh

@@ -1023,14 +1023,7 @@ if testtag AX_USE_DOXYGEN; then
         doxyadd ALIASES '"description=@DESCRIPTION@"'
         doxyadd ALIASES '"readme=@README_HTML@"'
         doxyadd ALIASES '"author=<a href="@AUTHOR_URL@" target="_blank">@AUTHOR_NAME@</a>"'
-        # hack plantuml for doxygen < 1.8.11
-        if test "1.8.11" = $((echo "1.8.11"; doxygen -v) | sort -V | head -1); then
-            doxyreplace PLANTUML_JAR_PATH '"@top_srcdir@/doc/plantuml.jar"'
-        else
-            doxyadd ALIASES '"startuml{1}=@image html \\1\\n@image latex \\1\\n\\if DontIgnorePlantUMLCode"'
-            doxyadd ALIASES '"enduml=\\endif"'
-            doxyadd IMAGE_PATH '"gen-uml-images"'
-        fi
+        doxyreplace PLANTUML_JAR_PATH '"@top_srcdir@/doc/plantuml.jar"'
         doxyreplace ENABLE_PREPROCESSING YES
         doxyreplace MACRO_EXPANSION YES
         doxyadd PREDEFINED '"NAMESPACE=@PACKAGE_NAME@"'