在win下使用gcc编译ruby，ext模块编译出现错误

在编译ext文件夹下的模块时，有几个模块总是出现如下错误，请问如何解决？是否需要打什么补丁？谢谢

ruby版本 1.9.1 RC1

错误信息：
cp ../.././ext/bigdecimal/lib/bigdecimal/newton.rb ../../.ext/common/bigdecimal
mkdir -p ../../.ext/common/bigdecimal
cp ../.././ext/bigdecimal/lib/bigdecimal/util.rb ../../.ext/common/bigdecimal
make[1]: Leaving directory `/d/ruby-1.9.1-rc1/ext/bigdecimal'
compiling continuation
make[1]: Entering directory `/d/ruby-1.9.1-rc1/ext/continuation'
make[1]: *** No rule to make target `ruby.h', needed by `continuation.o'. Stop.

make[1]: Leaving directory `/d/ruby-1.9.1-rc1/ext/continuation'
make: *** [exts] Error 1