[lwip-users] print debug message in lwip130

[Kevin]

Hi, 

I am trying to print some debug message in lwip1.3.0, but run into this error during compilation:
===========================================
.....
Compiling:  ../externals/lwip130/src/lwip-1.3.0/src/core/init.c
Compiling:  ../externals/lwip130/src/lwip-1.3.0/src/core/mem.c
../externals/lwip130/src/lwip-1.3.0/src/core/mem.c: In function 'mem_malloc':
../externals/lwip130/src/lwip-1.3.0/src/core/mem.c:570: error: expected ')' before 'S16_F'
../externals/lwip130/src/lwip-1.3.0/src/core/mem.c:570: warning: spurious trailing '%' in format
make[1]: *** [/cygdrive/c/Dominator/V0/debug/objs/mem.o] Error 1
make: *** [/cygdrive/c/Dominator/V0/../externals/lwip130/src] Error 2
===========================================

What I see at line 570 of mem.c is:
============================
  LWIP_DEBUGF(MEM_DEBUG | 2, ("mem_malloc: could not allocate %"S16_F" bytes\n", (s16_t)size));
============================

I am using powerpc-eabi-gcc for this compilation. What does this error mean and how to fix it? Can anybody give a hint for this message?

Thank you in advance!

Kevin