[libxslt] CMake: Only add postfixes if MSVC

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 5430f5d7bf030d6de49be33ce3b9c0a43d035b39
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Sat Mar 20 21:58:40 2021 +0100

    CMake: Only add postfixes if MSVC

 CMakeLists.txt | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/CMakeLists.txt b/CMakeLists.txt
index a352bc0e..541cbc59 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -243,7 +243,7 @@ set_target_properties(
        VERSION ${PROJECT_VERSION}
 )
 
-if(WIN32)
+if(MSVC)
        if(BUILD_SHARED_LIBS)
                set_target_properties(
                        LibXslt
@@ -325,7 +325,7 @@ set_target_properties(
        VERSION ${LIBEXSLT_VERSION}
 )
 
-if(WIN32)
+if(MSVC)
        if(BUILD_SHARED_LIBS)
                set_target_properties(
                        LibExslt