How do I get ruby-svm to look for libraries in macports' /opt/local?

Question

I want to install Ruby SVM. I already have macports with normal settings, and installed libsvm via port just fine. But when I go to compile rubysvm, it barfs. :(

Ruby SVM: http://rubysvm.cilibrar.com/download/ (most links are 404 though) libsvm: http://www.csie.ntu.edu.tw/~cjlin/libsvm/

Try this:

sudo port install libsvm
wget http://debian.cilibrar.com/debian/pool/main/libs/libsvm-ruby/libsvm-ruby_2.8.4.orig.tar.gz
tar -xzf libsvm-ruby_2.8.4.orig.tar.gz
cd libsvm-ruby-2.8.4
./configure

... and you get the error:

...
checking libsvm/svm.h usability... no
checking libsvm/svm.h presence... no
checking for libsvm/svm.h... no
Error, cannot find LIBSVM svm.h header.

I've tried this, without success:

export DYLD_LIBRARY_PATH=/opt/local/include/:/opt/local/lib/
(... ditto for C_INCLUDE_PATH, LD_LIBRARY_PATH, CPATH, & LIBRARY_PATH)
LDFLAGS="-I/opt/local/include -L/opt/local/lib" CPPFLAGS="-I/opt/local/include -L/opt/local/lib" ./configure

How do I fix this?

Answer 1

libsvm-ruby assumes libsvm installs its header in PREFIX/include/libsvm/svm.h, but the macports package puts it in /opt/local/include.

It's a kludge, but the easiest fix is to manually make the directory /opt/local/include/libsvm and move/copy the svm.h header there. You may still need to run your configure command with the LDFLAGS and CPPFLAGS settings since it looks like the macports install doesn't update pkg-config (which libsvm-ruby uses to try to find the compiler flags).

I'd report this as a package bug to the macports maintainer. If you understand macport's Portfiles, you can probably even provide a patch.

Update: I haven't actually tried this, so there may be other issues once you get past the header file detection.

Update 2: I was able to get past configure with:

sudo mkdir /opt/local/include/libsvm
sudo cp /opt/local/include/svm /opt/local/include/libsvm/
CPPFLAGS=-I/opt/local/include LIBS=-L/opt/local/lib ./configure

But libsvm-ruby appears to depend on obstack.h, which doesn't exist natively on OS X. Based on this, there might be a way to copy in the files that you need, but you'll need to patch the libsvm-ruby main.cpp and Makefile to link that in.

Good luck!