Adding include paths for library compilation

I have an existing c++ code base which I would like to make available as an Arduino library. The code is currently organised into a number of folders. The build system I've been using adds each folder to the compiler search path. Header files are included using only the file name (eg. #include "a.h") and not the full path (eg. #include "utils\a.h").

This causes an issue when compiled under the Arduino IDE because it doesn't know where to find the included headers as they are not necessarily in the same folder as the .cpp file that includes them.

What are my options for getting this to compile under the Arduino IDE? Do I need to change all my #include statements to include the path? Or (preferably) is there a way I can tell the Arduino IDE which sub-folders to search when compiling the code?

There is a plan to add this functionality:

but that has not yet been merged, and even after it is merged and released, use of the feature will make your library not work for the many Arduino users who insist on using outdated versions of the IDE.

Thanks for the replies. I guess I'll have the update all of my #includes.