[libxml2] CMake: Only add postfixes if MSVC

[Nick Wellnhofer <nwellnhof src gnome org>]

commit d3a02679b87443c6034cf36ad0c007070edf663b
Author: Christopher Degawa <ccom randomderp com>
Date:   Mon Mar 15 13:44:34 2021 -0500

    CMake: Only add postfixes if MSVC
    
    Currently, it catches mingw-w64 in there as well, but mingw-w64 follows
    linux-like naming with no weird postfixes
    
    Signed-off-by: Christopher Degawa <ccom randomderp com>

 CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/CMakeLists.txt b/CMakeLists.txt
index d6ee9ec7..a437717b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -496,7 +496,7 @@ set_target_properties(
        VERSION ${PROJECT_VERSION}
 )
 
-if(WIN32)
+if(MSVC)
        if(BUILD_SHARED_LIBS)
                set_target_properties(
                        LibXml2