--- a/cmake/InstallDirs.cmake
+++ b/cmake/InstallDirs.cmake
@@ -8,7 +8,7 @@
 # Set installation directories
 #
 
-if(WIN32
+if(MSVC
    AND NOT CMAKE_CROSSCOMPILING
    AND CMAKE_SIZEOF_VOID_P EQUAL 4)
   if(NOT CMAKE_INSTALL_BINDIR)