bootstrap broken: nan() does not match prototype

[Gerald Pfeifer]

i386-unknown-freebsd4.8 fails to bootstrap due to a problem with nan():

/bin/sh ../libtool --tag CC --mode=compile /files/pfeifer/OBJ-0123-1028/gcc/xgcc -B/files/pfeifer/OBJ-0123-1028/gcc/ -B/sw/gcc-current/i386-unknown-freebsd4.8/bin/ -B/sw/gcc-current/i386-unknown-freebsd4.8/lib/ -isystem /sw/gcc-current/i386-unknown-freebsd4.8/include -isystem /sw/gcc-current/i386-unknown-freebsd4.8/sys-include -DHAVE_CONFIG_H -I. -I/sw/test/gcc/cvs/libstdc++-v3/libmath -I..   -O2 -g -O2  -O2 -g -O2 -c -o nan.lo /sw/test/gcc/cvs/libstdc++-v3/libmath/nan.c
/files/pfeifer/OBJ-0123-1028/gcc/xgcc -B/files/pfeifer/OBJ-0123-1028/gcc/ -B/sw/gcc-current/i386-unknown-freebsd4.8/bin/ -B/sw/gcc-current/i386-unknown-freebsd4.8/lib/ -isystem /sw/gcc-current/i386-unknown-freebsd4.8/include -isystem /sw/gcc-current/i386-unknown-freebsd4.8/sys-include -DHAVE_CONFIG_H -I. -I/sw/test/gcc/cvs/libstdc++-v3/libmath -I.. -O2 -g -O2 -O2 -g -O2 -c /sw/test/gcc/cvs/libstdc++-v3/libmath/nan.c  -fPIC -DPIC -o .libs/nan.o
/sw/test/gcc/cvs/libstdc++-v3/libmath/nan.c: In function `nan':
/sw/test/gcc/cvs/libstdc++-v3/libmath/nan.c:36: error: number of arguments doesn't match prototype
cc1: error: prototype declaration
gmake[4]: *** [nan.lo] Error 1
gmake[4]: Leaving directory `/files/pfeifer/OBJ-0123-1028/i386-unknown-freebsd4.8/libstdc++-v3/libmath'
gmake[3]: *** [all-recursive] Error 1

libstdc++-v3/libmath/nan.c used the signature
  double nan ()
whereas gcc/builtins.def has
  BT_FN_DOUBLE_CONST_STRING

Gerald