PaulS:
There are no paths involved in the build process.
I think you need to have another look at how the build process works.
The library header files are included from their location in the "libraries" directories.
(user and system) by using an include path. This requires handing include paths to the compiler.
And that is one of the problems. The current build process requires that a separate include path
be given to the compiler for every single library used and those include paths are "learned" by
scanning through the users primary sketch file.
This is not a good way of doing things as it creates problems like what the Dr is seeing
and also keeps library modules from compiling that use other libraries unless the primary sketch
file has the additional, and unneeded by the sketch, header includes added to its source in order
to trick the IDE into modifying the include path to allow all the other modules to be able to locate
their header files.
While I wouldn't do that way, it is ok to scan the users sketch file to learn of libraries to try to make things
simpler for the users sketch file. Where I have the problem is requiring the user to modify his sketch file in order to get
library or other modules to compile.
--- bill