>gem install ruby-debug-base19 --version=0.11.26 -- --configure-options --with-ruby-include="C:\PROGRA~2\Ruby\1.9.3-p0\include\ruby-1.9.1\ruby-1.9.3-p0" Temporarily enhancing PATH to include DevKit... Building native extensions. This could take a while... ERROR: Error installing ruby-debug-base19: ERROR: Failed to build gem native extension. C:/PROGRA~2/Ruby/1.9.3-p0/bin/ruby.exe extconf.rb --configure-options --with-ruby-include=C:\PROGRA~2\Ruby\1.9.3-p0\include\ruby-1.9.1\ruby-1.9.3-p0 checking for rb_method_entry_t.called_id in method.h... yes checking for vm_core.h... yes checking for iseq.h... yes checking for insns.inc... yes checking for insns_info.inc... yes checking for eval_intern.h... yes checking for struct iseq_line_info_entry in vm_core.h,iseq.h... no checking for struct iseq_insn_info_entry in vm_core.h,iseq.h... yes checking for if rb_iseq_compile_with_option was added an argument filepath... yes creating Makefile make generating ruby_debug-i386-mingw32.def compiling breakpoint.c breakpoint.c:3:21: fatal error: vm_core.h: No such file or directory compilation terminated. make: *** [breakpoint.o] Error 1 Gem files will remain installed in C:/PROGRA~2/Ruby/1.9.3-p0/lib/ruby/gems/1.9.1/gems/ruby-debug-base19-0.11.26 for inspection. Results logged to C:/PROGRA~2/Ruby/1.9.3-p0/lib/ruby/gems/1.9.1/gems/ruby-debug-base19-0.11.26/ext/ruby_debug/gem_make.out
Luis Lavena lent me a hand on this, but that couldn't solve the problem.
Update: Moving your Ruby installation to a path without spaces fixes the problem. I thought
PROGRA~2could work just find. Thanks Luis once again.