message: drake: curl: use our own zlib.pc
  Curl's configure.ac checks pkg-config *before* --with-zlib, so we
  might end up using the system's copy instead ours.
diff: @@ -591,6 +591,10 @@ def configure(cxx_toolkit = None,
  curl_env = {
  'CC': cxx_toolkit.c,
  'CFLAGS': '-w',
  + # Be sure to control pkg-config, otherwise, because curl's
  + # configure.ac checks pkg-config *before* --with-zlib, we might
  + # end up using the system's copy instead ours.
  + 'PKG_CONFIG_PATH': drake.path_build(zlib_prefix, absolute = True) / 'lib' / 'pkgconfig',
  }
  if cxx_toolkit.architecture is drake.architecture.arm:
  curl_configure_args.append('--host=%s' % cxx_toolkit.cxx[:-4])
  @@ -608,9 +612,6 @@ def configure(cxx_toolkit = None,
  # configure is making a runtime library availability check
  curl_env['LD_LIBRARY_PATH'] = \
  str(drake.path_build(curl_prefix / 'lib', absolute = True))
  - elif cxx_toolkit.os is drake.os.linux:
  - path = drake.path_build(zlib_prefix, absolute = True) / 'lib' / 'pkgconfig'
  - curl_env['PKG_CONFIG_PATH'] = str(path)
  curl_dependency_libs = curl_openssl_libs + curl_zlib_libs
  curl_headers = [
  'include/curl/typecheck-gcc.h',
  