Properly handling conditional functions in header

[Evan Klinger]

Hello all,
We have a shared library that we install which includes the header
which contains the functions available in the library. However,
depending upon the ./configure options, not all of the functions will
be available and won't be compiled in. Thus we would like to remove
these from the header file. Currently they are wrapped in #ifdefs
which come from config.h but once the header is installed, the
config.h is no longer necessary or used. So I'm wondering what the
best approach is to remove the function prototypes from the header for
the functions that were not compiled in.

Thank you
Evan