CITOS 6.9
（类似于问题：Can't find the PostgreSQL client library (libpq)但那是在macos上而不是centos上，所以这些解决方案不起作用。）
Ruby 2.1.8（尝试过2.2）
Rails 4.2.6（试用5.0）
邮政9.3
我正在尝试安装pg gem：
gem install pg -- --with-pqlib=/usr/lib64/libpqxx-4.0.so --with-pg-config=/usr/pgsql-9.3/bin/pg_config
我一直在尝试为它提供不同的库，但它遇到的问题是一些
PQconnectdb()函数。错误如下rails以前是用pg安装在这台计算机上的，但是在更新之后发生了一些事情。有什么想法吗？
ERROR: Error installing pg:
ERROR: Failed to build gem native extension.
current directory: /home/myusername/.rvm/gems/ruby-2.1.8/gems/pg-0.14.1/ext
/home/myusername/.rvm/rubies/ruby-2.1.8/bin/ruby -r ./siteconf20170425-12873-191077o.rb extconf.rb --with-pqlib=/usr/lib64/libpqxx-4.0.so --with-pg-config=/usr/pgsql-9.3/bin/pg_config
Using config values from /usr/pgsql-9.3/bin/pg_config
extconf.rb:34: warning: Insecure world writable dir /opt/anaconda in PATH, mode 040777
checking for libpq-fe.h... yes
checking for libpq/libpq-fs.h... yes
checking for pg_config_manual.h... yes
checking for PQconnectdb() in -l/usr/lib64/libpqxx-4.0.so... no
checking for PQconnectdb() in -llibpq... no
checking for PQconnectdb() in -lms/libpq... no
Can't find the PostgreSQL client library (libpq)
*** 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.
已安装的pg库：
Installed Packagespostgresql93.x86_64 9.3.16-1PGDG.rhel6
postgresql93-contrib.x86_64 9.3.16-1PGDG.rhel6
postgresql93-debuginfo.x86_64 9.3.16-1PGDG.rhel6
postgresql93-devel.x86_64 9.3.16-1PGDG.rhel6
postgresql93-docs.x86_64 9.3.16-1PGDG.rhel6
postgresql93-libs.x86_64 9.3.16-1PGDG.rhel6
postgresql93-odbc.x86_64 09.06.0100-1PGDG.rhel6
postgresql93-odbc-debuginfo.x86_64 09.03.0400-1PGDG.rhel6
postgresql93-plperl.x86_64 9.3.16-1PGDG.rhel6
postgresql93-plpython.x86_64 9.3.16-1PGDG.rhel6
postgresql93-pltcl.x86_64 9.3.16-1PGDG.rhel6
postgresql93-server.x86_64 9.3.16-1PGDG.rhel6
postgresql93-tcl.x86_64 2.1.1-1.rhel6
postgresql93-tcl-debuginfo.x86_64 2.1.1-1.rhel6
postgresql93-test.x86_64 9.3.16-1PGDG.rhel6 最佳答案
你试过这个吗？
$ sudo su
$ env ARCHFLAGS="-arch x86_64" gem install pg