MDEV-22613 Windows - reduce package size

Liposuction of about 20% package size is achieved by using
linker /OPT:REF,ICF and compile option /Gw

cmake/os/Windows.cmake

@@ -186,9 +186,8 @@ IF(MSVC)
    STRING(REGEX REPLACE "/STACK:([^ ]+)" "" CMAKE_${type}_LINKER_FLAGS "${CMAKE_${type}_LINKER_FLAGS}")
    STRING(REGEX REPLACE "/INCREMENTAL:([^ ]+)" "/INCREMENTAL:NO" CMAKE_${type}_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_${type}_LINKER_FLAGS_RELWITHDEBINFO}")
    STRING(REGEX REPLACE "/INCREMENTAL$" "/INCREMENTAL:NO" CMAKE_${type}_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_${type}_LINKER_FLAGS_RELWITHDEBINFO}")
-   SET(CMAKE_${type}_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_${type}_LINKER_FLAGS_RELWITHDEBINFO} /OPT:REF")
    IF(NOT CLANG_CL)
-     SET(CMAKE_${type}_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_${type}_LINKER_FLAGS_RELWITHDEBINFO} /release")
+     STRING(APPEND CMAKE_${type}_LINKER_FLAGS_RELWITHDEBINFO " /release /OPT:REF,ICF")
    ENDIF()
    IF(DYNAMIC_UCRT_LINK AND (MSVC_CRT_TYPE STREQUAL "/MT"))
      FOREACH(config RELEASE RELWITHDEBINFO DEBUG MINSIZEREL)
@@ -208,6 +207,8 @@ IF(MSVC)
   IF (NOT CLANG_CL)
     STRING(APPEND CMAKE_C_FLAGS " /MP")
     STRING(APPEND CMAKE_CXX_FLAGS " /MP")
+    STRING(APPEND CMAKE_C_FLAGS_RELWITHDEBINFO " /Gw")
+    STRING(APPEND CMAKE_CXX_FLAGS_RELWITHDEBINFO " /Gw")
   ENDIF()
   
   #TODO: update the code and remove the disabled warnings