编译vim插件Comannd-T的C扩展失败

按照安装文档执行了如下命令：

ruby extconf.rb
make
后来make之后报错：

compiling ext.c
In file included from /usr/include/ruby-1.9.1/ruby/ruby.h:24:0,

             from /usr/include/ruby-1.9.1/ruby.h:32,
             from matcher.h:24,
             from ext.c:24:

/usr/include/ruby-1.9.1/i486-linux/ruby/config.h:20:0: warning: "_FILE_OFF
SET_BITS" redefined [enabled by default]
:0:0: note: this is the location of the previous definition
compiling match.c
In file included from /usr/include/ruby-1.9.1/ruby/ruby.h:24:0,

             from /usr/include/ruby-1.9.1/ruby.h:32,
             from match.h:24,
             from match.c:25:

/usr/include/ruby-1.9.1/i486-linux/ruby/config.h:20:0: warning: "_FILE_OFF
SET_BITS" redefined [enabled by default]
:0:0: note: this is the location of the previous definition
compiling matcher.c
In file included from /usr/include/stdlib.h:25:0,

             from matcher.c:24:

/usr/include/features.h:283:34: error: token "=" is not valid in preproces
sor expressions
In file included from /usr/include/ruby-1.9.1/ruby/ruby.h:24:0,

             from /usr/include/ruby-1.9.1/ruby.h:32,
             from matcher.h:24,
             from matcher.c:26:

/usr/include/ruby-1.9.1/i486-linux/ruby/config.h:20:0: warning: "_FILE_OFF
SET_BITS" redefined [enabled by default]
:0:0: note: this is the location of the previous definition
matcher.c: In function ‘CommandTMatcher_sorted_matches_for’:
matcher.c:162:24: error: ‘PROCESSOR_COUNT’ undeclared (first use in this f
unction)
matcher.c:162:24: note: each undeclared identifier is reported only once f
or each function it appears in
make: * [matcher.o] Error 1
哪里出问题了？