doc: add initial doxygen documentation

Makefile.am

@@ -2,6 +2,9 @@ SUBDIRS = src
 if ENABLE_TOOLS
 SUBDIRS += tools
 endif
+if HAVE_DOXYGEN
+SUBDIRS += doc
+endif
 
 ACLOCAL_AMFLAGS = -I m4
 

configure.ac

@@ -14,6 +14,11 @@ AC_PROG_CC
 AC_PROG_CXX
 AM_PROG_AR
 
+AC_CHECK_PROGS([DOXYGEN], [doxygen])
+if test -z "$DOXYGEN";
+   then AC_MSG_WARN([Doxygen not found - continuing without Doxygen support])
+fi
+
 case "${host_os}" in
   "")
     SYS=unknown
@@ -59,5 +64,8 @@ PKG_CHECK_MODULES([GNUTLS], [gnutls >= 3.1])
 AC_ARG_ENABLE([tools], AS_HELP_STRING([--disable-tools],[Disable tools (CLI DHT node)]),,build_tools=yes)
 AM_CONDITIONAL(ENABLE_TOOLS, test x$build_tools == xyes)
 
+AM_CONDITIONAL([HAVE_DOXYGEN], [test -n "$DOXYGEN"])
+AM_COND_IF([HAVE_DOXYGEN], [AC_CONFIG_FILES([doc/Doxyfile doc/Makefile])])
+
 AC_CONFIG_FILES([Makefile src/Makefile tools/Makefile opendht.pc])
 AC_OUTPUT

doc/Makefile.am

+doxyfile.stamp:
+	$(DOXYGEN) Doxyfile
+	echo stamp > doxyfile.stamp
+
+CLEANFILES = doxyfile.stamp
+
+all-local: doxyfile.stamp
+clean-local:
+	rm -rf $(top_srcdir)/doc/man $(top_srcdir)/doc/html