Here is the output: 1. Main.out from a link that succeeds. 2. GtkHelloWorld.out, a sample program from gtk+hs, compiled with ghc -v -fglasgow-exts -lgtkHS GtkHelloWorld.hs `gtkhs-config --cflags` `gtkhs-config --libs` `gtk-config --cflags` `gtk-config --libs`

In fact, you are right, there is a -L/usr/lib before -lgmp. Maybe the libgmp.a included with ghc should be renamed, for example libgmp_ghc.a

That would be one solution, yes. On your system, if you remove /usr/lib/libgmp.a (and /usr/lib/libgmp.so if you have one), does it work? You only need these files if you intend to build any software which depends on having GMP version 2, which is unlikely since GMP 3 is source-compatible with GMP 2. Cheers, Simon