Removed and fixed some AC_SUBST configure entries.

dependencies to applications.

not supporting it. It hasn't been functioning for years anyway, so this is
just finally stating what already was true. And a cleanup at the same time.

--features was used

protocols that are disabled.

Here's a stab at a consolidation of the SSL detection heuristics into
configure. Source files aren't changed by this patch, except for setup.h and
the various config*.h files.  Within the configure script, OPENSSL_ENABLED is
used to determine if SSL is being used or not, and outside configure,
USE_SSLEAY means the same thing; this could be even further unified some day.

Now, when SSL is not detected, configure skips the various checks that are
dependent on SSL, speeding up the configure process and avoiding complications
with cross compiles.  I also updated all the architecture- specific config
files I could see, but I couldn't test them.

is not a good thing, as recent gccs for example complain if it is /usr/include

Right now, we just output "" until we think of something better.

to compile libcurl stuff without any prior knowledge:

cc=`curl-config --cc`
cflags=`curl-config --cflags`
libs=`curl-config --libs`

$cc $flags $libs -o example example.c

Or if you prefer, the oh-so-cool single-line version:

`curl-config --cc --cflags --libs` -o example example.c

when building anything with libcurl

which libcurl itself is installed in.

that have been built-in