+AS_IF([test -z "$FIG2DEV" -o -z "$MAKEINFO"],
+ [GINAC_WARNING([Documentation may not build, because fig2dev/texinfo is missing.])])
+AS_IF([test -z "$DOXYGEN"],
+ [GINAC_WARNING([Reference manual will not build, because doxygen is missing.])])
+AS_IF([test -z "$LATEX" -o -z "$PDFLATEX" -o -z "$DVIPS"],
+ [GINAC_WARNING([Some documentation formats may not build, because latex/pdflatex/dvips is missing.])])
+
+dnl generate boilerplate code for the (new) parser.
+dnl Only developers need this tool.
+AC_PATH_PROG(AUTOGEN, autogen, "")
+AC_CHECK_FILE([ginac/parser/builtin_fcns.cpp], [],
+ [AS_IF([test -z "$AUTOGEN"], [GINAC_ERROR([Source will not compile, because autogen is missing.])])])