How do I specify LDFLAGS and CPPFLAGS for ./configure?

Question

I am using a Mac running OS X 10.8.3. I am trying to compile cgminer 3.0.0. On my first run of ./configure I got the message:

checking for LIBCURL... no
checking for LIBCURL... no
configure: error: Missing required libcurl dev >= 7.18.2

So I installed the latest version of libcurl using homebrew:

brew install curl

That seemed to do the trick. I got this message:

downloaded: /Library/Caches/Homebrew/curl-7.30.0.tar.gz
==> ./configure --prefix=/usr/local/Cellar/curl/7.30.0
==> make install
==> Caveats
This formula is keg-only: so it was not symlinked into /usr/local.

Mac OS X already provides this software and installing another version in
parallel can cause all kinds of trouble.

The libcurl provided by Leopard is too old for CouchDB to use.

Generally there are no consequences of this for you. If you build your
own software and it requires this formula, you'll need to add to your
build variables:

    LDFLAGS:  -L/usr/local/opt/curl/lib
    CPPFLAGS: -I/usr/local/opt/curl/include

==> Summary
/usr/local/Cellar/curl/7.30.0: 75 files, 2.0M, built in 61 seconds

Okay, so it's installed but not symlinked into /usr/local, that's fine with me. I tried this:

export LDFLAGS=-L/usr/local/opt/curl/lib
export CPPFLAGS=-I/usr/local/opt/curl/include
./configure

But I got the same message: configure: error: Missing required libcurl dev >= 7.18.2

So I tried this:

env LDFLAGS=-L/usr/local/opt/curl/lib CPPFLAGS=-I/usr/local/opt/curl/include ./configure

I'm still getting the "missing required libcurl" message. Any ideas?

Answer 1

After some more thorough investigation, I determined that the configure file for cgminer does not pay attention to LDFLAGS or CPPFLAGS when testing for libcurl. Instead, it checks for LIBCURL_CFLAGS and LIBCURL_LIBS. So, I tried:

export LIBCURL_CFLAGS=-I/usr/local/opt/curl/include
export LIBCURL_LIBS=-L/usr/local/opt/curl/lib
./configure

and I got:

checking for LIBCURL... yes

And the rest of the configuration went off without a hitch. SUCCESS!