respect destdir for compat symlink

StandAlone/CMakeLists.txt

@@ -121,7 +121,7 @@ if(ENABLE_GLSLANG_INSTALL)
     # Create the same symlink at install time
     install(CODE "execute_process( \
                       COMMAND ${CMAKE_COMMAND} -E ${link_method} $<TARGET_FILE_NAME:glslang-standalone> ${legacy_glslang_name} \
-                      WORKING_DIRECTORY ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_BINDIR})")
+                      WORKING_DIRECTORY \$ENV{DESTDIR}/${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_BINDIR})")
 
     if(ENABLE_SPVREMAPPER)
         install(TARGETS spirv-remap EXPORT glslang-targets)