fixup! cmake: Add position independent code support

PIC/PIE is not a thing in Windows PE format. Therefore, warnings are
rather making noise than providing valuable feedback.

CMakeLists.txt

@@ -80,7 +80,8 @@ include(CheckPIESupported)
 check_pie_supported(OUTPUT_VARIABLE check_pie_output LANGUAGES CXX)
 if(CMAKE_CXX_LINK_PIE_SUPPORTED)
   set(CMAKE_POSITION_INDEPENDENT_CODE ON)
-else()
+elseif(NOT WIN32)
+  # The warning is superfluous for Windows.
   message(WARNING "PIE is not supported at link time: ${check_pie_output}")
   list(APPEND configure_warnings "Position independent code disabled.")
 endif()