我是Ruby的新手。当我尝试“gem install therubyracer”时，出现以下错误：
C:\Users\Desktop>gem install therubyracer
Temporarily enhancing PATH to include DevKit...
Building native extensions. This could take a while...
ERROR: Error installing therubyracer:
ERROR: Failed to build gem native extension.
C:/Ruby193/bin/ruby.exe extconf.rb
checking for main() in -lpthread... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.
Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=C:/Ruby193/bin/ruby
--with-pthreadlib
--without-pthreadlib
--enable-debug
--disable-debug
C:/Ruby193/lib/ruby/gems/1.9.1/gems/libv8-3.16.14.3/ext/libv8/location.rb:15:in `initialize': No such file or directory - C:/Ruby193/lib/ruby/gems/1.9.1/gems/libv8-3.16.14.3/ext/libv8/.location.yml (Errno::ENOENT)
from C:/Ruby193/lib/ruby/gems/1.9.1/gems/libv8-3.16.14.3/ext/libv8/location.rb:15:in `open'
from C:/Ruby193/lib/ruby/gems/1.9.1/gems/libv8-3.16.14.3/ext/libv8/location.rb:15:in `load!'
from C:/Ruby193/lib/ruby/gems/1.9.1/gems/libv8-3.16.14.3/lib/libv8.rb:6:in `configure_makefile'
from extconf.rb:32:in `<main>'
Gem files will remain installed in C:/Ruby193/lib/ruby/gems/1.9.1/gems/therubyracer-0.12.0 for inspection.
Results logged to C:/Ruby193/lib/ruby/gems/1.9.1/gems/therubyracer-0.12.0/ext/v8/gem_make.out
C:\Users\Desktop>
我尝试在Google和Stackoverflow的一些类似帖子中搜索，但都没有解决这个问题。
mkmf.log
（注：mkmf.log是一个文件名，无需翻译）
have_library: checking for main() in -lpthread... -------------------- no
"gcc -o conftest -IC:/Ruby193/include/ruby-1.9.1/i386-mingw32 -IC:/Ruby193/include/ruby-1.9.1/ruby/backward -IC:/Ruby193/include/ruby-1.9.1 -I. -DFD_SETSIZE=2048 -DFD_SETSIZE=2048 -O3 -fno-omit-frame-pointer -g -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wimplicit-function-declaration conftest.c -L. -LC:/Ruby193/lib -L. -lmsvcrt-ruby191 -lshell32 -lws2_32 -limagehlp -lshlwapi "
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <winsock2.h>
4: #include <windows.h>
5: int main(int argc, char **argv)
6: {
7: return 0;
8: }
/* end */
"gcc -o conftest -IC:/Ruby193/include/ruby-1.9.1/i386-mingw32 -IC:/Ruby193/include/ruby-1.9.1/ruby/backward -IC:/Ruby193/include/ruby-1.9.1 -I. -DFD_SETSIZE=2048 -DFD_SETSIZE=2048 -O3 -fno-omit-frame-pointer -g -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wimplicit-function-declaration conftest.c -L. -LC:/Ruby193/lib -L. -lmsvcrt-ruby191 -lpthread -lshell32 -lws2_32 -limagehlp -lshlwapi "
conftest.c: In function 't':
conftest.c:7:53: error: 'main' undeclared (first use in this function)
conftest.c:7:53: note: each undeclared identifier is reported only once for each function it appears in
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <winsock2.h>
4: #include <windows.h>
5:
6: /*top*/
7: int t() { void ((*volatile p)()); p = (void ((*)()))main; return 0; }
8: int main(int argc, char **argv)
9: {
10: if (argc > 1000000) {
11: printf("%p", &t);
12: }
13:
14: return 0;
15: }
/* end */
"gcc -o conftest -IC:/Ruby193/include/ruby-1.9.1/i386-mingw32 -IC:/Ruby193/include/ruby-1.9.1/ruby/backward -IC:/Ruby193/include/ruby-1.9.1 -I. -DFD_SETSIZE=2048 -DFD_SETSIZE=2048 -O3 -fno-omit-frame-pointer -g -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wimplicit-function-declaration conftest.c -L. -LC:/Ruby193/lib -L. -lmsvcrt-ruby191 -lpthread -lshell32 -lws2_32 -limagehlp -lshlwapi "
conftest.c: In function 't':
conftest.c:7:1: warning: implicit declaration of function 'main'
conftest.c:10:6: warning: 'argc' is used uninitialized in this function
conftest.c:7:5: note: 'argc' was declared here
c:/devkit193/mingw/bin/../lib/gcc/mingw32/4.5.2/../../../../mingw32/bin/ld.exe: cannot find -lpthread
collect2: ld returned 1 exit status
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <winsock2.h>
4: #include <windows.h>
5:
6: /*top*/
7: int t() { main(); return 0; }
8: int main(int argc, char **argv)
9: {
10: if (argc > 1000000) {
11: printf("%p", &t);
12: }
13:
14: return 0;
15: }
/* end */
--------------------