third_party/protobuf: Update to HEAD (83d681ee2c)

third_party/protobuf/cmake/protobuf-config-version.cmake.in

-set(PACKAGE_VERSION @protobuf_VERSION@)
+set(PACKAGE_VERSION "@protobuf_VERSION@")
+set(${PACKAGE_FIND_NAME}_VERSION_PRERELEASE "@protobuf_VERSION_PRERELEASE@" PARENT_SCOPE)
+
+# Prerelease versions cannot be passed in directly via the find_package command,
+# so we allow users to specify it in a variable
+if(NOT DEFINED "${PACKAGE_FIND_NAME}_FIND_VERSION_PRERELEASE")
+  set("${${PACKAGE_FIND_NAME}_FIND_VERSION_PRERELEASE}" "")
+else()
+  set(PACKAGE_FIND_VERSION ${PACKAGE_FIND_VERSION}-${${PACKAGE_FIND_NAME}_FIND_VERSION_PRERELEASE})
+endif()
+set(PACKAGE_FIND_VERSION_PRERELEASE "${${PACKAGE_FIND_NAME}_FIND_VERSION_PRERELEASE}")
+
+# VERSION_EQUAL ignores the prerelease strings, so we use STREQUAL.
+if(PACKAGE_FIND_VERSION STREQUAL PACKAGE_VERSION)
+  set(PACKAGE_VERSION_EXACT TRUE)
+endif()
+
+set(PACKAGE_VERSION_COMPATIBLE TRUE) #Assume true until shown otherwise
+
+if(NOT PACKAGE_FIND_VERSION_MAJOR EQUAL "@protobuf_VERSION_MAJOR@")
+  set(PACKAGE_VERSION_COMPATIBLE FALSE)
+elseif(PACKAGE_FIND_VERSION VERSION_GREATER PACKAGE_VERSION)
+  set(PACKAGE_VERSION_COMPATIBLE FALSE)
+elseif(PACKAGE_FIND_VERSION VERSION_EQUAL PACKAGE_VERSION)
+  # Do not match prerelease versions to non-prerelease version requests.
+  if(NOT "@protobuf_VERSION_PRERELEASE@" STREQUAL "" AND PACKAGE_FIND_VERSION_PRERELEASE STREQUAL "")
+    message(AUTHOR_WARNING "To use this prerelease version of ${PACKAGE_FIND_NAME}, set ${PACKAGE_FIND_NAME}_FIND_VERSION_PRERELEASE to '@protobuf_VERSION_PRERELEASE@' or greater.")
+    set(PACKAGE_VERSION_COMPATIBLE FALSE)
+  endif()
+
+  # Not robustly SemVer compliant, but protobuf never uses '.' separated prerelease identifiers.
+  if(PACKAGE_FIND_VERSION_PRERELEASE STRGREATER "@protobuf_VERSION_PRERELEASE@")
+    set(PACKAGE_VERSION_COMPATIBLE FALSE)
+  endif()
+endif()
+
+# Check and save build options used to create this package
+macro(_check_and_save_build_option OPTION VALUE)
+  if(DEFINED ${PACKAGE_FIND_NAME}_${OPTION} AND
+    NOT ${PACKAGE_FIND_NAME}_${OPTION} EQUAL VALUE)
+    set(PACKAGE_VERSION_UNSUITABLE TRUE)
+  endif()
+  set(${PACKAGE_FIND_NAME}_${OPTION} ${VALUE})
+endmacro()
+_check_and_save_build_option(WITH_ZLIB @protobuf_WITH_ZLIB@)
+_check_and_save_build_option(MSVC_STATIC_RUNTIME @protobuf_MSVC_STATIC_RUNTIME@)
+_check_and_save_build_option(BUILD_SHARED_LIBS @protobuf_BUILD_SHARED_LIBS@)
+
+# if the installed or the using project don't have CMAKE_SIZEOF_VOID_P set, ignore it:
+if(NOT "${CMAKE_SIZEOF_VOID_P}" STREQUAL "" AND NOT "@CMAKE_SIZEOF_VOID_P@" STREQUAL "")
+  # check that the installed version has the same 32/64bit-ness as the one which is currently searching:
+  if(NOT CMAKE_SIZEOF_VOID_P STREQUAL "@CMAKE_SIZEOF_VOID_P@")
+    math(EXPR installedBits "@CMAKE_SIZEOF_VOID_P@ * 8")
+    set(PACKAGE_VERSION "${PACKAGE_VERSION} (${installedBits}bit)")
+    set(PACKAGE_VERSION_UNSUITABLE TRUE)
+  endif()
+endif()
+