Can't build on OS X

Here's the error:

spidermonkey.c:5:22: error: debugger.h: No such file or directory

spidermonkey.c: In function ‘Init_spidermonkey’:

spidermonkey.c:16: warning: implicit declaration of function ‘init_Johnson_SpiderMonkey_Debugger’

make: *** [spidermonkey.o] Error 1

rake aborted!

Command failed with status (2): [make...]

/Library/Ruby/Gems/1.8/gems/johnson-1.0.0/rakefile:76

(See full trace by running task with --trace)

Gem files will remain installed in /Library/Ruby/Gems/1.8/gems/johnson-1.0.0 for inspection.

Results logged to /Library/Ruby/Gems/1.8/gems/johnson-1.0.0/gem_make.out

rake aborted!

Command failed with status (1): [sudo gem install --local pkg/*.gem...]

(See full trace by running task with --trace)

[~/git/others/johnson] patnakajima(master)$ gcc -v

Using built-in specs.

Target: i686-apple-darwin9

Configured with: /var/tmp/gcc/gcc-5478~1/src/configure --disable-checking -enable-werror --prefix=/usr --mandir=/share/man --enable-languages=c,objc,c++,obj-c++ --program-transform-name=/^[cg][^.-]*$/s/$/-4.0/ --with-gxx-include-dir=/include/c++/4.0.0 --with-slibdir=/usr/lib --build=powerpc-apple-darwin9 --with-arch=apple --with-tune=generic --program-prefix= --host=i686-apple-darwin9 --target=i686-apple-darwin9

Thread model: posix

gcc version 4.0.1 (Apple Inc. build 5478)