[racket] build error from 5.1.2 on i686-pc-linux-gnu

Ciao,

  while building Racket 5.1.2 from racket-5.1.2-src-unix.tgz
on a i686-pc-linux-gnu with:

  $ mkdir '=build'
  $ ../src/configure --enable-shared --disable-static
  $ make

I get the following error:

make normal-bin
...
make[4]: Entering directory `/home/marco/var/build/devel/racket-5.1.2/=build/racket/gc2'
env XFORM_PRECOMP=yes ../racketcgc -cqu ../../../src/racket/gc2/xform.rkt --setup . --cpp "gcc -E -I./.. -I../../../src/racket/gc2/../include -I/usr/local/lib/libffi-3.0.8/include   -pthread    -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -DMZ_USES_SHARED_LIB "  --keep-lines -o xsrc/precomp.h ../../../src/racket/gc2/precomp.c
/opt/racket/5.1.1/lib/racket/collects/racket/stxparam.rkt:25:31: compile: unbound identifier in module (in phase 1, transformer environment) in: syntax-local-certifier

-- 
Marco Maggi