在嘗試安裝pg gem時找不到‘libpq-fe.h標頭我正在使用RubyonRails 3.1預版本。我喜歡使用PostgreSQL，但問題是安裝pg寶石。它給出了以下錯誤：$ gem install pgBuilding native extensions.  This could take a while...ERROR:  Error installing pg:    ERROR: Failed to build gem native extension.        /home/u/.rvm/rubies/ruby-1.9.2-p0/bin/ruby extconf.rbchecking for pg_config... noNo pg_config... trying anyway. If building fails, please try again with --with-pg-config=/path/to/pg_configchecking for libpq-fe.h... noCan't find the 'libpq-fe.h header*** extconf.rb failed ***Could not create Makefile due to some reason, probably lack ofnecessary libraries and/or headers.  Check the mkmf.log file for moredetails.  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=/home/u/.rvm/rubies/ruby-1.9.2-p0/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    --without-pg-config    --with-pg_config    --without-pg_configGem files will remain installed in /home/u/.rvm/gems/ruby-1.9.2-p0/gems/pg-0.11.0 for inspection.Results logged to /home/u/.rvm/gems/ruby-1.9.2-p0/gems/pg-0.11.0/ext/gem_make.out我該如何解決這個問題？