Installation on Solaris, problem with 'gplc' and 'as'

I like to install gprolog-1.3.0 on Solaris. I have

/tmp/gprolog-1.3.0> as -V
as: Sun Compiler Common 10 Patch 05/06/2005
/tmp/gprolog-1.3.0> gas -V
GNU assembler version 2.15 (sparc-sun-solaris2.10) using BFD version 2.15


I started configure with --with-as=/usr/sfw/bin/gas, hoping that using GNU
assembler removes the problem (some missing quotation marks) I had. But
the problem remains, see below.

/tmp/gprolog-1.3.0/src> configure --prefix=/usr/central --with-as=/usr/sfw/bin/gas
checking for gcc... gcc
checking for C compiler default output file name... a.out
...

/tmp/gprolog-1.3.0/src> gmake
(cd EnginePl; gmake config)
gmake[1]: Entering directory `/tmp/gprolog-1.3.0/src/EnginePl'
gcc  -O3 -fomit-frame-pointer  -o pl_config pl_config.c
./pl_config

        -------------------------------
        --- GNU PROLOG INSTALLATION ---
        -------------------------------

GNU Prolog version: 1.3.0 (Jan 4 2007)
Operating system  : solaris2.10
Processor         : sparc
Size of a word    : 32 bits
C compiler        : gcc
C flags           : -O3 -fomit-frame-pointer
C flags machine   :
Loader flags      : -L/usr/local/pkgs/glibc/solaris./lib/
Loader libraries  : -lm -lsocket -lnsl
Use line editor   : Yes
Use piped consult : Yes
Use sockets       : Yes
Use FD solver     : Yes
Use machine regs. : Yes
Used register(s)  : g6 g7

        ------------------------------

...

gplc -c -C '-O3 -fomit-frame-pointer -funsigned-char' callinf_supp.c
gplc -c -C '-O3 -fomit-frame-pointer -funsigned-char' bc_supp.c
gplc -c foreign.wam
as: "/var/tmp/gplcKhjVKc.s", line 109: error: quoted-string operand
required
as: "/var/tmp/gplcKhjVKc.s", line 112: error: quoted-string operand
required
compilation failed
gmake[1]: *** [foreign.o] Error 1
gmake[1]: Leaving directory `/tmp/gprolog-1.3.0/src/BipsPl'
gmake: *** [all] Error 1


How can I solve that problem?