我正在尝试使用 heroku 让 Rails 与 Cygwin 一起工作，但是当我这样做时遇到了问题
bundle install
我很确定 postgres 已安装（我从 Cygwin 的 setup.exe 中安装了标题中带有“postgres”的所有内容，但遇到了问题
gem install pg
，我无法理解错误消息。
如果这个问题是微不足道的，请道歉；这是我第一次尝试学习 RoR。错误日志如下。提前致谢！
/usr/bin/ruby.exe extconf.rb
checking for pg_config... yes
Using config values from /usr/bin/pg_config
checking for libpq-fe.h... yes
checking for libpq/libpq-fs.h... yes
checking for pg_config_manual.h... yes
checking for PQconnectdb() in -lpq... yes
checking for PQconnectionUsedPassword()... no
checking for PQisthreadsafe()... yes
checking for PQprepare()... yes
checking for PQexecParams()... yes
checking for PQescapeString()... yes
checking for PQescapeStringConn()... yes
checking for PQgetCancel()... yes
checking for lo_create()... yes
checking for pg_encoding_to_char()... yes
checking for pg_char_to_encoding()... yes
checking for PQsetClientEncoding()... yes
checking for rb_encdb_alias()... no
checking for rb_enc_alias()... no
checking for struct pgNotify.extra in libpq-fe.h... yes
checking for unistd.h... yes
checking for ruby/st.h... no
checking for st.h... yes
creating extconf.h
creating Makefile
make
gcc -I. -I. -I/usr/lib/ruby/1.8/i386-cygwin -I. -DRUBY_EXTCONF_H=\"extconf.h\" -I/us /include -g -O2 -pipe -fno-strict-aliasing -c pg.c
gcc -I. -I. -I/usr/lib/ruby/1.8/i386-cygwin -I. -DRUBY_EXTCONF_H=\"extconf.h\" -I/usr/include -g -O2 -pipe -fno-strict-aliasing -c pg_connection.c
gcc -I. -I. -I/usr/lib/ruby/1.8/i386-cygwin -I. -DRUBY_EXTCONF_H=\"extconf.h\" -I/usr/include -g -O2 -pipe -fno-strict-aliasing -c pg_result.c
gcc -shared -s -o pg_ext.so pg.o pg_connection.o pg_result.o -L. -L/usr/lib -L. -L/usr/lib -Wl,--enable-auto-image-base,--enable-auto-import,--export-all -lruby -lpq -lrt -ldl -lcrypt
pg_connection.o: In function 'pgconn_connection_needs_password':
/usr/lib/ruby/gems/1.8/gems/pg-0.13.1/ext/pg_connection.c:714: undefined reference to `_PQconnectionNeedsPassword'
pg_connection.o: In function 'pgconn_connection_used_password':
/usr/lib/ruby/gems/1.8/gems/pg-0.13.1/ext/pg_connection.c:727: undefined reference to `_PQconnectionUsedPassword'
pg_connection.o: In function 'pgconn_lotruncate':
/usr/lib/ruby/gems/1.8/gems/pg-0.13.1/ext/pg_connection.c:2991: undefined reference to `_lo_truncate'
collect2: ld returned 1 exit status
Makefile:152: recipe for target `pg_ext.so' failed
make: *** [pg_ext.so] Error 1