I did this (in the startup script) on a 64bit debian system with clang 3.6 installed:
export CC=clang
export CXX=clang
export CFLAGS="-fobjc-nonfragile-abi -fblocks"
./configure
(I need to produce a foundation with objc2.0 support which is the reason why I can't use the ones in the debian repo)
I got this:
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Installation of GNUstep Gui failed. Send the /Users/afink/development/gnustep-startup-0.32.0/build/logs.tar.gz
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File attached: