gcc40 build error on AMD64

[Markus Trippelsdorf]

I cannot build gcc40 on my AMD64 machine because of the following error
(happens on 5.4 and CURRENT):

cc -c   -g -DENABLE_CHECKING -DENABLE_ASSERT_CHECKING -DIN_GCC   -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition  -Wno-error  -DHAVE_CONFIG_H -DGENERATOR_FILE -I/usr/local/include   -I. -Ibuild -I.././..//gcc-4.0-20050602/gcc -I.././..//gcc-4.0-20050602/gcc/build -I.././..//gcc-4.0-20050602/gcc/../include -I.././..//gcc-4.0-20050602/gcc/../libcpp/include -I/usr/local/include  \
 -o build/insn-conditions.o insn-conditions.c
insn-conditions.c:97: error: `flag_unsafe_math_optimizations' undeclared here (not in a function)
insn-conditions.c:97: error: initializer element is not constant
insn-conditions.c:97: error: (near initialization for `insn_conditions[10].value')
insn-conditions.c:97: warning: missing initializer
insn-conditions.c:97: warning: (near initialization for `insn_conditions[10].value')
insn-conditions.c:97: error: initializer element is not constant
insn-conditions.c:97: error: (near initialization for `insn_conditions[10]')
insn-conditions.c:101: error: initializer element is not constant
insn-conditions.c:101: error: (near initialization for `insn_conditions[11]')
insn-conditions.c:104: error: initializer element is not constant

Any ideas?
Thanks in advance.
--
Markus