With version 2.2.0 I get the following error when pushing to Heroku. Version 2.0.0 works fine. I opened a support ticket with Heroku and they forked my repo with version 2.2.0 and were able to deploy successfully, so it's a mystery why the build error only happens for some Heroku accounts. Here is the error from the NPM build log:

make: Entering directory /tmp/build_3avqh7rkfufxa/node_modules/pg/build' CXX(target) Release/obj.target/binding/src/binding.o ../src/binding.cc: In member function 'char* Connection::EscapeIdentifier(const char*)': ../src/binding.cc:367: error: 'PQescapeIdentifier' was not declared in this scope ../src/binding.cc: In member function 'char* Connection::EscapeLiteral(const char*)': ../src/binding.cc:373: error: 'PQescapeLiteral' was not declared in this scope make: *** [Release/obj.target/binding/src/binding.o] Error 1 make: Leaving directory/tmp/build_3avqh7rkfufxa/node_modules/pg/build'
gyp ERR! build error
gyp ERR! stack Error: make failed with exit code: 2
gyp ERR! stack at ChildProcess.onExit (/tmp/node-npm-mskG/node_modules/node-gyp/lib/build.js:267:23)
gyp ERR! stack at ChildProcess.EventEmitter.emit (events.js:98:17)
gyp ERR! stack at Process.ChildProcess._handle.onexit (child_process.js:789:12)
gyp ERR! System Linux 3.8.11-ec2
gyp ERR! command "node" "/tmp/node-npm-mskG/node_modules/node-gyp/bin/node-gyp.js" "rebuild"
gyp ERR! cwd /tmp/build_3avqh7rkfufxa/node_modules/pg
gyp ERR! node -v v0.10.13
gyp ERR! node-gyp -v v0.10.0
gyp ERR! not ok

ref@0.1.3 install /tmp/build_3avqh7rkfufxa/node_modules/pg/node_modules/ref
node-gyp rebuild

make: Entering directory /tmp/build_3avqh7rkfufxa/node_modules/pg/node_modules/ref/build' CXX(target) Release/obj.target/binding/src/binding.o SOLINK_MODULE(target) Release/obj.target/binding.node SOLINK_MODULE(target) Release/obj.target/binding.node: Finished COPY Release/binding.node make: Leaving directory/tmp/build_3avqh7rkfufxa/node_modules/pg/node_modules/ref/build'