component/postgresql: include citext extension

component/postgresql/buildout.cfg

 [buildout]
-extends = 
+extends =
+  ../icu/buildout.cfg
   ../openssl/buildout.cfg
+  ../pkgconfig/buildout.cfg
   ../readline/buildout.cfg
   ../zlib/buildout.cfg
   ../ncurses/buildout.cfg
@@ -30,10 +32,13 @@ configure-options =
   --without-libxslt
 # build core PostgreSQL + pg_trgm contrib extension for GitLab
 # unaccent contrib extension is for peertube
-make-targets = install && make -C contrib/pg_trgm/ install && make -C contrib/unaccent/ install
+# citext contrib extension is for metabase
+make-targets = install && make -C contrib/pg_trgm/ install && make -C contrib/unaccent/ install && make -C contrib/citext/ install
 environment =
-  CPPFLAGS=-I${zlib:location}/include -I${readline:location}/include -I${openssl:location}/include -I${ncurses:location}/lib
-  LDFLAGS=-L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib -L${readline:location}/lib -Wl,-rpath=${readline:location}/lib -L${openssl:location}/lib -Wl,-rpath=${openssl:location}/lib -L${ncurses:location}/lib -Wl,-rpath=${ncurses:location}/lib -L${perl:location}/libs-c -Wl,-rpath=${perl:location}/libs-c
+  PATH=${pkgconfig:location}/bin:%(PATH)s
+  CPPFLAGS=-I${zlib:location}/include -I${readline:location}/include -I${openssl:location}/include -I${ncurses:location}/include
+  LDFLAGS=-L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib -L${readline:location}/lib -Wl,-rpath=${readline:location}/lib -L${openssl:location}/lib -Wl,-rpath=${openssl:location}/lib -L${ncurses:location}/lib -Wl,-rpath=${ncurses:location}/lib -L${perl:location}/libs-c -Wl,-rpath=${perl:location}/libs-c -Wl,-rpath=${icu:location}/lib
+  PKG_CONFIG_PATH=${icu:location}/lib/pkgconfig/
 
 [postgresql10]
 <= postgresql-common