Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension. /usr/local/bin/ruby extconf.rb --with-pg-config=/usr/pgsql-9.1/bin/pg_config Using config values from /usr/pgsql-9.1/bin/pg_config sh: /usr/pgsql-9.1/bin/pg_config: No such file or directory sh: /usr/pgsql-9.1/bin/pg_config: No such file or directory checking for libpq-fe.h... *** 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=/usr/local/bin/ruby --with-pg --without-pg --with-pg-dir --without-pg-dir --with-pg-include --without-pg-include=${pg-dir}/include --with-pg-lib --without-pg-lib=${pg-dir}/lib --with-pg-config /usr/local/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': The compiler failed to generate an executable file. (RuntimeError) You have to install development tools first. from /usr/local/lib/ruby/1.9.1/mkmf.rb:506:in `try_cpp' from /usr/local/lib/ruby/1.9.1/mkmf.rb:970:in `block in find_header' from /usr/local/lib/ruby/1.9.1/mkmf.rb:790:in `block in checking_for' from /usr/local/lib/ruby/1.9.1/mkmf.rb:284:in `block (2 levels) in postpone' from /usr/local/lib/ruby/1.9.1/mkmf.rb:254:in `open' from /usr/local/lib/ruby/1.9.1/mkmf.rb:284:in `block in postpone' from /usr/local/lib/ruby/1.9.1/mkmf.rb:254:in `open' from /usr/local/lib/ruby/1.9.1/mkmf.rb:280:in `postpone' from /usr/local/lib/ruby/1.9.1/mkmf.rb:789:in `checking_for' from /usr/local/lib/ruby/1.9.1/mkmf.rb:969:in `find_header' from extconf.rb:41:in `' Gem files will remain installed in /usr/local/lib/ruby/gems/1.9.1/gems/pg-0.14.1 for inspection. Results logged to /usr/local/lib/ruby/gems/1.9.1/gems/pg-0.14.1/ext/gem_make.out An error occurred while installing pg (0.14.1), and Bundler cannot continue. Make sure that `gem install pg -v '0.14.1'` succeeds before bundling.
这个错误的原因是没有PostgreSql的dev包，不能成功编译PostgreSql的客户端；解决办法有两个：
1）安装dev包
用包管理来安装，RedHat系是
Debian系是：
2）如果你不打算用PostgreSql来作为Redmine的数据库，可以用下面的命令来忽略相应的gem：
你还可以忽略sqlite和rmagick（都有依赖的）：