In order to work with the new blas/lapack setup from the sci overlay, libs and apps must use pkg-config(1) to get the compile args.
Igraph uses AC_CHECK_LIB() in its configure.in. That needs to be changed to calls to PKG_CHECK_MODULES() in order for the compile to succeed.
Also, the ebuild has arpack, blas and lapack USE flags, but ignores them and hardcodes the econf call to use the external libs. The latter is, of course, OK but then the flags should be dropped and anything which specifies any of those flags in dependencies update, too. Fixing this bug would be an opportune time also to fix the useless USE flags.
+*igraph-0.6.4 (21 Feb 2013)
+ 21 Feb 2013; Justin Lecher <email@example.com> -igraph-0.5.4.ebuild,
+ +igraph-0.6.4.ebuild, +files/igraph-0.6.4-unbundle.patch, metadata.xml:
+ Version Bump; unbundle correctly and use pkg-config to detect sys libs,
+ #445114; fix tests, #421773; drop old