ruby extconf.rb install postgres
checking for cygwin32_socket() in -lwsock32... no
checking for socket() in -lsocket... no
checking for gethostbyname() in -linet... no
checking for gethostbyname() in -lnsl... yes
checking for sys/un.h... yes
checking for socket()... yes
checking for hsterror()... no
checking for gethostname()... yes
checking for PQsetdbLogin() in -lpq... yes
checking for PQsetClientEncoding()... yes
checking for pg_encoding_to_char()... yes
checking for PQescapeString()... yes
creating Makefile

make
gcc -I. -I. -I/usr/lib/ruby/1.8/i486-linux -I. -DHAVE_SYS_UN_H -DHAVE_SOCKET -DHAVE_GETHOSTNAME -DHAVE_PQSETCLIENTENCODING -DHAVE_PG_ENCODING_TO_CHAR -DHAVE_PQESCAPESTRING  -fPIC
  -c postgres.c
postgres.c:18:22: error: libpq-fe.h: No such file or directory
postgres.c:19:70: error: libpq/libpq-fs.h: No such file or directory
postgres.c:35: error: expected ')' before '*' token
postgres.c:44: error: expected specifier-qualifier-list before 'PGconn'
postgres.c:49: error: expected ')' before '*' token
postgres.c: In function 'free_pgconn':
postgres.c:54: error: expected declaration specifiers before 'PGconn'
postgres.c: In function 'pgconn_s_connect':
postgres.c:69: error: 'PGconn' undeclared (first use in this function)
postgres.c:69: error: (Each undeclared identifier is reported only once
postgres.c:69: error: for each function it appears in.)
postgres.c:69: error: 'conn' undeclared (first use in this function)
postgres.c:112: error: 'CONNECTION_BAD' undeclared (first use in this function)
postgres.c:113: warning: passing argument 2 of 'rb_raise' makes pointer from integer without a cast
postgres.c: At top level:
postgres.c:254: error: expected '=', ',', ';', 'asm' or '__attribute__' before '*' token
postgres.c:257: error: expected identifier or '(' before '{' token
postgres.c:283: error: expected '=', ',', ';', 'asm' or '__attribute__' before '*' token
postgres.c:286: error: expected identifier or '(' before '{' token
postgres.c: In function 'pgconn_exec':
postgres.c:298: error: 'PGconn' undeclared (first use in this function)
postgres.c:298: error: 'conn' undeclared (first use in this function)
postgres.c:299: error: 'PGresult' undeclared (first use in this function)
postgres.c:299: error: 'result' undeclared (first use in this function)
postgres.c:307: warning: passing argument 2 of 'rb_raise' makes pointer from integer without a cast
postgres.c:312: error: 'PGRES_TUPLES_OK' undeclared (first use in this function)
postgres.c:313: error: 'PGRES_COPY_OUT' undeclared (first use in this function)
postgres.c:314: error: 'PGRES_COPY_IN' undeclared (first use in this function)
postgres.c:315: error: 'PGRES_EMPTY_QUERY' undeclared (first use in this function)
postgres.c:316: error: 'PGRES_COMMAND_OK' undeclared (first use in this function)
postgres.c:319: error: 'PGRES_BAD_RESPONSE' undeclared (first use in this function)
postgres.c:320: error: 'PGRES_FATAL_ERROR' undeclared (first use in this function)