Initial set of files.

The make install target is not working for .proto files, but otherwise
it seems to work.

cmake/config.pc.in

@@ -0,0 +1,26 @@
+# Copyright 2019 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+prefix=@CMAKE_INSTALL_PREFIX@
+exec_prefix=${prefix}/@CMAKE_INSTALL_BINDIR@
+libdir=${prefix}/@CMAKE_INSTALL_LIBDIR@
+includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@
+
+Name: @GOOGLE_CLOUD_CPP_PC_NAME@
+Description: @GOOGLE_CLOUD_CPP_PC_DESCRIPTION@
+Requires: @GOOGLE_CLOUD_CPP_PC_REQUIRES@
+Version: @DOXYGEN_PROJECT_NUMBER@
+
+Libs: -L${libdir} @GOOGLE_CLOUD_CPP_PC_LIBS@
+Cflags: -I${includedir}