No way to pass -I to $(CC), or otherwise add to the include path

[Kyle Hamilton]

There's no way to pass -I to $(CC), or otherwise add to $(CC)'s include
path.  Not every user of autoconf (nor of the software that autoconf is used
to create configure scripts for) has root on their development boxes.  In
this case, I'm attempting to include OpenSSL [no comments or suggestions
about GNUtls please] from my user install directory, to better simulate a
system without SSL/TLS libraries.  The main include file
(/home/kyle/include/openssl/ssl.h) is included properly, but gcc does not
have -I/home/kyle/include passed to it.  This means that the subheaders that
ssl.h attempts to include are not found.

I've searched high and low and can't find a way to do this.  Please make it
possible to manipulate GCC's include path, as well as its library path.
Thank you.

-Kyle Hamilton