Question

I’m trying to use the GNU autoconf/automake toolchain for the first time, so the answer to my question might be trivial.

The program needs OpenGL/GLUT where the headers and libraries are installed in a non standard location. I found these macros that should do all the checking for me. I’m simply calling it with AX_CHECK_GLUT. How do I make the macro find the libraries? I’m looking for something like

./configure –with-glut-dir=/home/hanno/glut

More generally: What is the normal way of dealing with non-standard library locations in an autoconf script? Of course, I can play around with CPPFLAGS and LIBS variables, but I have the feeling that I’m missing something.

Answer 1

The way the Autotools are designed, a package author doesn’t have to do anything to support prerequisite installed in non-standard locations. The output of ./configure --help includes the following lines:

LDFLAGS     linker flags, e.g. -L<lib dir> if you have libraries in a
            nonstandard directory <lib dir>
CPPFLAGS    C/C++/Objective C preprocessor flags, e.g. -I<include dir> if
            you have headers in a nonstandard directory <include dir>

Therefore, if the installer has a prerequisite installed in a non standard location, he will have to issue

./configure CPPFLAGS=-I/non-standard-dir/include LDFLAGS=-L/non-standard-dir/lib

Because CPPFLAGS and LDFLAGS are used by configure checks and Makefile rules, everything should work.

Some package authors like to offer a --with-package=location option as a shorthand for the above, but this normally is not the purpose of --with-package options. These options are better used to specify whether an optional package should be used, or how a prerequisite should be fulfilled.