Fix issue with version.rc

cmake/libprotobuf-lite.cmake

@@ -48,9 +48,11 @@ set(libprotobuf_lite_includes
   ${protobuf_source_dir}/src/google/protobuf/wire_format_lite.h
 )
 
+if (MSVC)
 set(libprotobuf_lite_rc_files
   ${CMAKE_CURRENT_BINARY_DIR}/version.rc
 )
+endif()
 
 add_library(libprotobuf-lite ${protobuf_SHARED_OR_STATIC}
   ${libprotobuf_lite_files} ${libprotobuf_lite_includes} ${libprotobuf_lite_rc_files})

cmake/libprotobuf.cmake

@@ -112,9 +112,11 @@ set(libprotobuf_includes
   ${protobuf_source_dir}/src/google/protobuf/wrappers.pb.h
 )
 
+if (MSVC)
 set(libprotobuf_rc_files
   ${CMAKE_CURRENT_BINARY_DIR}/version.rc
 )
+endif()
 
 add_library(libprotobuf ${protobuf_SHARED_OR_STATIC}
   ${libprotobuf_lite_files} ${libprotobuf_files} ${libprotobuf_includes} ${libprotobuf_rc_files})

cmake/libprotoc.cmake

@@ -161,9 +161,11 @@ set(libprotoc_headers
   ${protobuf_source_dir}/src/google/protobuf/compiler/zip_writer.h
 )
 
+if (MSVC)
 set(libprotoc_rc_files
   ${CMAKE_CURRENT_BINARY_DIR}/version.rc
 )
+endif()
 
 set(js_well_known_types_sources
   ${protobuf_source_dir}/src/google/protobuf/compiler/js/well_known_types/any.js

cmake/protoc.cmake

@@ -2,9 +2,11 @@ set(protoc_files
   ${protobuf_source_dir}/src/google/protobuf/compiler/main.cc
 )
 
+if (MSVC)
 set(protoc_rc_files
   ${CMAKE_CURRENT_BINARY_DIR}/version.rc
 )
+endif()
 
 add_executable(protoc ${protoc_files} ${protoc_rc_files})
 target_link_libraries(protoc libprotobuf libprotoc)