Add the 0.18 docs.

json-c-0.18/doc/CMakeLists.txt

@@ -0,0 +1,16 @@
+# generate doxygen documentation for json-c API
+
+find_package(Doxygen)
+
+if (DOXYGEN_FOUND)
+
+	configure_file(${CMAKE_CURRENT_SOURCE_DIR}/Doxyfile.in
+	  ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile)
+	message(STATUS "Wrote ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile")
+
+	add_custom_target(doc
+	COMMAND ${DOXYGEN_EXECUTABLE} ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile)
+
+else (DOXYGEN_FOUND)
+	message("Warning: doxygen not found, the 'doc' target will not be included")
+endif(DOXYGEN_FOUND)