我的 rails 环境是用 windows installer 安装的。不知错误是什么原因，错误记录：

C:\Sites>gem install caldecott Temporarily enhancing PATH to include DevKit... Building native extensions. This could take a while... ERROR: Error installing caldecott: ERROR: Failed to build gem native extension.

D:/RailsInstaller/Ruby1.9.3/bin/ruby.exe extconf.rb checking for rb_trap_immediate in ruby.h,rubysig.h... no checking for rb_thread_blocking_region()... yes checking for inotify_init() in sys/inotify.h... no checking for __NR_inotify_init in sys/syscall.h... no checking for writev() in sys/uio.h... no checking for rb_thread_check_ints()... yes checking for rb_time_new()... yes checking for windows.h... yes checking for winsock.h... yes checking for main() in -lkernel32... yes checking for main() in -lrpcrt4... yes checking for main() in -lgdi32... yes checking for main() in -lssl... no creating Makefile

make generating rubyeventmachine-i386-mingw32.def compiling binder.cpp cc1plus.exe: warning: command line option "-Wdeclaration-after-statement" is val id for C/ObjC but not for C++ cc1plus.exe: warning: command line option "-Wimplicit-function-declaration" is v alid for C/ObjC but not for C++ In file included from project.h:137:0, from binder.cpp:20: binder.h:35:34: warning: type qualifiers ignored on function return type In file included from project.h:138:0, from binder.cpp:20: em.h:91:47: warning: type qualifiers ignored on function return type em.h:92:76: warning: type qualifiers ignored on function return type em.h:93:56: warning: type qualifiers ignored on function return type em.h:95:57: warning: type qualifiers ignored on function return type em.h:96:60: warning: type qualifiers ignored on function return type em.h:97:58: warning: type qualifiers ignored on function return type em.h:98:55: warning: type qualifiers ignored on function return type em.h:99:36: warning: type qualifiers ignored on function return type em.h:101:47: warning: type qualifiers ignored on function return type em.h:106:42: warning: type qualifiers ignored on function return type em.h:123:45: warning: type qualifiers ignored on function return type em.h:132:36: warning: type qualifiers ignored on function return type In file included from project.h:145:0, from binder.cpp:20: eventmachine.h:45:61: warning: type qualifiers ignored on function return type eventmachine.h:46:112: warning: type qualifiers ignored on function return type eventmachine.h:47:69: warning: type qualifiers ignored on function return type eventmachine.h:49:73: warning: type qualifiers ignored on function return type eventmachine.h:62:75: warning: type qualifiers ignored on function return type eventmachine.h:63:74: warning: type qualifiers ignored on function return type eventmachine.h:64:77: warning: type qualifiers ignored on function return type eventmachine.h:65:41: warning: type qualifiers ignored on function return type In file included from project.h:145:0, from binder.cpp:20: eventmachine.h:99:60: warning: type qualifiers ignored on function return type eventmachine.h58: warning: type qualifiers ignored on function return type eventmachine.h:102:60: warning: type qualifiers ignored on function return type eventmachine.h:105:41: warning: type qualifiers ignored on function return type compiling cmain.cpp cc1plus.exe: warning: command line option "-Wdeclaration-after-statement" is val id for C/ObjC but not for C++ cc1plus.exe: warning: command line option "-Wimplicit-function-declaration" is v alid for C/ObjC but not for C++ In file included from project.h:137:0, from cmain.cpp:20: binder.h:35:34: warning: type qualifiers ignored on function return type In file included from project.h:138:0, from cmain.cpp:20: em.h:91:47: warning: type qualifiers ignored on function return type em.h:92:76: warning: type qualifiers ignored on function return type em.h:93:56: warning: type qualifiers ignored on function return type em.h:95:57: warning: type qualifiers ignored on function return type em.h:96:60: warning: type qualifiers ignored on function return type em.h:97:58: warning: type qualifiers ignored on function return type em.h:98:55: warning: type qualifiers ignored on function return type em.h:99:36: warning: type qualifiers ignored on function return type em.h:101:47: warning: type qualifiers ignored on function return type em.h:106:42: warning: type qualifiers ignored on function return type em.h:123:45: warning: type qualifiers ignored on function return type em.h:132:36: warning: type qualifiers ignored on function return type In file included from project.h:145:0, from cmain.cpp:20: eventmachine.h:45:61: warning: type qualifiers ignored on function return type eventmachine.h:46:112: warning: type qualifiers ignored on function return type eventmachine.h:47:69: warning: type qualifiers ignored on function return type eventmachine.h:49:73: warning: type qualifiers ignored on function return type eventmachine.h:62:75: warning: type qualifiers ignored on function return type eventmachine.h:63:74: warning: type qualifiers ignored on function return type eventmachine.h:64:77: warning: type qualifiers ignored on function return type eventmachine.h:65:41: warning: type qualifiers ignored on function return type In file included from project.h:145:0, from cmain.cpp:20: eventmachine.h:99:60: warning: type qualifiers ignored on function return type eventmachine.h58: warning: type qualifiers ignored on function return type eventmachine.h:102:60: warning: type qualifiers ignored on function return type eventmachine.h:105:41: warning: type qualifiers ignored on function return type cmain.cpp:98:71: warning: type qualifiers ignored on function return type cmain.cpp:109:122: warning: type qualifiers ignored on function return type cmain.cpp:119:79: warning: type qualifiers ignored on function return type cmain.cpp:129:83: warning: type qualifiers ignored on function return type cmain.cpp:260:85: warning: type qualifiers ignored on function return type cmain.cpp:270:84: warning: type qualifiers ignored on function return type cmain.cpp:280:88: warning: type qualifiers ignored on function return type cmain.cpp:290:51: warning: type qualifiers ignored on function return type cmain.cpp:300:70: warning: type qualifiers ignored on function return type cmain.cpp:320:55: warning: type qualifiers ignored on function return type cmain.cpp:546:70: warning: type qualifiers ignored on function return type cmain.cpp:669:68: warning: type qualifiers ignored on function return type cmain.cpp: In function 'int evma_send_file_data_to_connection(long unsigned int, const char*)': cmain.cpp:752:6: error: cannot convert 'stat*' to '_stati64*' for argument '2' t o 'int _fstati64(int, _stati64*)' make: *** [cmain.o] Error 1

Gem files will remain installed in D:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9 .1/gems/eventmachine-0.12.10 for inspection. Results logged to D:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/eventmach ine-0.12.10/ext/gem_make.out

C:\Sites>gem update --system Latest version currently installed. Aborting.