multiple inclusion of header files accross

[Aaron Case]

Hello,

Is there a ld switch to address the problem of multiple inclusion of header
files accross object files.  I have used #ifndef and #define to prevent
multiple inclusion within an object file successfully.

Or should this be address in the makefile?  The current structure of the
makefile compiles several objects and then links the objects together but,
but some header files are included in almost all the source files used to
make each object.

Or should this be addressed by reorganizing my header files and throwing in
a few extern keywords?

Thanks in advance?

Aaron Case