omniorb: fix build for uclinux

Add a patch to make configure correctly identify uclinux.

Also, disable build of shared libraries when PREFER_STATIC_LIB is set.
Otherwise, build for Blackfin fails further down the road.

Fixes:
http://autobuild.buildroot.net/results/c60/c60d880b620c47f4aa03cdf2e1bb85a526242d54/
http://autobuild.buildroot.net/results/01f/01f4e8a27831d6817b329fa23fe0bbabd7fd01c9/
http://autobuild.buildroot.net/results/a96/a96a06b825c14dc9fdf738225db50bc1de8b901a/



And many others.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Acked-by: Matt Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>