Another build error building 0.3-test-6

[Chris Kohlhepp]

This error does not happen on a fresh checkout. Had previous master 
build and did a checkout of 0.3-test-6.

Starting Clasp boehm-0.3 ... loading image... it takes a few seconds
Building cleavir clasp full version - loading compile-cclasp.lisp
Loading cleavir-system.lsp
Loading/compiling source: 
#P"/Applications/Clasp/clasp/build/clasp/Contents/Resources/lisp/kernel/contrib/sicl/Code/Cleavir/Input-output/packages.lisp"
Loading/compiling source: 
#P"/Applications/Clasp/clasp/build/clasp/Contents/Resources/lisp/kernel/contrib/sicl/Code/Cleavir/Input-output/io.lisp"

Condition of type: SIMPLE-ERROR

Noticed that the git command updating SICL contrib gives an error when 
not running a fresh checkout of 0.3-test-6.

By the way, 0.3-test-5 builds fine. But I'm not sure what the benefits 
of 0.3-test-5 over master are.

Best wishes

Chris Kohlhepp