Allow one to omit building libprotoc and protoc binaries

cmake/CMakeLists.txt

@@ -14,6 +14,7 @@ project(protobuf C CXX)
 # Options
 option(protobuf_BUILD_TESTS "Build tests" ON)
 option(protobuf_BUILD_EXAMPLES "Build examples" OFF)
+option(protobuf_BUILD_PROTOC_BINARIES "Build libprotoc and protoc compiler" ON)
 if (BUILD_SHARED_LIBS)
   set(protobuf_BUILD_SHARED_LIBS_DEFAULT ON)
 else (BUILD_SHARED_LIBS)
@@ -184,8 +185,10 @@ endif (protobuf_UNICODE)
 
 include(libprotobuf-lite.cmake)
 include(libprotobuf.cmake)
-include(libprotoc.cmake)
-include(protoc.cmake)
+if (protobuf_BUILD_PROTOC_BINARIES)
+  include(libprotoc.cmake)
+  include(protoc.cmake)
+endif (protobuf_BUILD_PROTOC_BINARIES)
 
 if (protobuf_BUILD_TESTS)
   include(tests.cmake)

cmake/install.cmake

@@ -5,10 +5,12 @@ configure_file(${CMAKE_CURRENT_SOURCE_DIR}/protobuf.pc.cmake
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/protobuf-lite.pc.cmake
                ${CMAKE_CURRENT_BINARY_DIR}/protobuf-lite.pc @ONLY)
 
-foreach(_library
-  libprotobuf-lite
-  libprotobuf
-  libprotoc)
+set(_protobuf_libraries libprotobuf-lite libprotobuf)
+if (protobuf_BUILD_PROTOC_BINARIES)
+    list(APPEND _protobuf_libraries libprotoc)
+endif (protobuf_BUILD_PROTOC_BINARIES)
+
+foreach(_library ${_protobuf_libraries})
   set_property(TARGET ${_library}
     PROPERTY INTERFACE_INCLUDE_DIRECTORIES
     $<BUILD_INTERFACE:${protobuf_source_dir}/src>
@@ -19,8 +21,10 @@ foreach(_library
     ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR} COMPONENT ${_library})
 endforeach()
 
-install(TARGETS protoc EXPORT protobuf-targets
-  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR} COMPONENT protoc)
+if (protobuf_BUILD_PROTOC_BINARIES)
+  install(TARGETS protoc EXPORT protobuf-targets
+    RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR} COMPONENT protoc)
+endif (protobuf_BUILD_PROTOC_BINARIES)
 
 install(FILES ${CMAKE_CURRENT_BINARY_DIR}/protobuf.pc ${CMAKE_CURRENT_BINARY_DIR}/protobuf-lite.pc DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig")
 
@@ -101,10 +105,18 @@ configure_file(protobuf-options.cmake
   ${CMAKE_INSTALL_CMAKEDIR}/protobuf-options.cmake @ONLY)
 
 # Allows the build directory to be used as a find directory.
-export(TARGETS libprotobuf-lite libprotobuf libprotoc protoc
-  NAMESPACE protobuf::
-  FILE ${CMAKE_INSTALL_CMAKEDIR}/protobuf-targets.cmake
-)
+
+if (protobuf_BUILD_PROTOC_BINARIES)
+  export(TARGETS libprotobuf-lite libprotobuf libprotoc protoc
+    NAMESPACE protobuf::
+    FILE ${CMAKE_INSTALL_CMAKEDIR}/protobuf-targets.cmake
+  )
+else (protobuf_BUILD_PROTOC_BINARIES)
+  export(TARGETS libprotobuf-lite libprotobuf
+    NAMESPACE protobuf::
+    FILE ${CMAKE_INSTALL_CMAKEDIR}/protobuf-targets.cmake
+  )
+endif (protobuf_BUILD_PROTOC_BINARIES)
 
 install(EXPORT protobuf-targets
   DESTINATION "${CMAKE_INSTALL_CMAKEDIR}"