[cmake] Remove linking to std::filesystem.

Applications/FileIO/CMakeLists.txt

@@ -32,7 +32,7 @@ target_link_libraries(
            $<$<BOOL:${OGS_BUILD_GUI}>:QtBase>
            $<$<TARGET_EXISTS:shp>:shp>
            $<$<TARGET_EXISTS:SwmmInterface>:SwmmInterface>
-    PRIVATE MeshLib GitInfoLib std::filesystem
+    PRIVATE MeshLib GitInfoLib
 )
 
 configure_file(

BaseLib/CMakeLists.txt

@@ -12,7 +12,6 @@ target_link_libraries(
     BaseLib
     PUBLIC Boost::boost
            spdlog::spdlog
-           std::filesystem
            tclap
            $<$<BOOL:${MSVC}>:WinMM> # needed for timeGetTime
            $<$<BOOL:${OGS_BUILD_GUI}>:Qt5::Xml>

Tests/xdmfdiff/CMakeLists.txt

 ogs_add_executable(xdmfdiff xdmfdiff.cpp)
-target_link_libraries(xdmfdiff OgsXdmf GitInfoLib std::filesystem tclap)
+target_link_libraries(xdmfdiff OgsXdmf GitInfoLib tclap)
 install(PROGRAMS $<TARGET_FILE:xdmfdiff> DESTINATION bin)