diff --git a/hmatrix-glpk.cabal b/hmatrix-glpk.cabal
--- a/hmatrix-glpk.cabal
+++ b/hmatrix-glpk.cabal
@@ -1,11 +1,11 @@
 Name:               hmatrix-glpk
-Version:            0.3.0
+Version:            0.3.1
 License:            GPL
 License-file:       LICENSE
 Author:             Alberto Ruiz
 Maintainer:         Alberto Ruiz <aruiz@um.es>
 Stability:          experimental
-Homepage:           http://perception.inf.um.es/hmatrix
+Homepage:           https://github.com/albertoruiz/hmatrix
 Synopsis:           Linear Programming based on GLPK
 Description:
  Simple interface to linear programming functions provided by GLPK.
@@ -35,6 +35,7 @@
     extra-libraries:    glpk
 
     if os(OSX)
+        extra-lib-dirs: /usr/lib
         extra-lib-dirs: /opt/local/lib/
         include-dirs: /opt/local/include/
         extra-lib-dirs: /usr/local/lib/
@@ -44,5 +45,5 @@
 
 source-repository head
     type:     git
-    location: https://github.com/AlbertoRuiz/hmatrix
+    location: https://github.com/albertoruiz/hmatrix
 
diff --git a/lib/Numeric/LinearProgramming.hs b/lib/Numeric/LinearProgramming.hs
--- a/lib/Numeric/LinearProgramming.hs
+++ b/lib/Numeric/LinearProgramming.hs
@@ -214,7 +214,7 @@
 
 -----------------------------------------------------
 
-foreign import ccall "c_simplex_sparse" c_simplex_sparse
+foreign import ccall unsafe "c_simplex_sparse" c_simplex_sparse
     :: CInt -> CInt                  -- rows and cols
     -> CInt -> CInt -> Ptr Double    -- coeffs
     -> CInt -> CInt -> Ptr Double    -- bounds