He shouldn't have needed to edit the script at all. Here is the relevant part for the CFLAGS from the script:
Code:
elif [ "$ARCH" = "x86_64" ]; then
SLKCFLAGS="-O2 -fPIC"
LIBDIRSUFFIX="64"
fi
And here is the configure part:
Code:
./configure \
--prefix=/usr \
--libdir=/usr/lib${LIBDIRSUFFIX} \
--sysconfdir=/etc \
--localstatedir=/var \
--disable-static \
--build=$ARCH-slackware-linux
All the stuff is already in there. It's something set in his environment that's messing it up. His /usr/lib64/libgobject-2.0.so.0.1800.4 looks fine, but it's saying file in wrong format. I'll bet that somehow some 32bit and 64bit stuff got mixed up.
edit: @ollebanan: When you tried to rebuild it with ARCH=x86_64 ./ORBit2.SlackBuild, did you delete your edited slackbuild script and use a redownloaded one?