include/prsht.h: guard preprocessor use of _WIN32_IE

[Gerald Pfeifer]

Similar to the previous patch; this one only triggering a few couple
times during a build, not thousands.
         
Gerald                                                                 
         
ChangeLog:                                                             
Guard preprocessor use of _WIN32_IE.

diff --git a/include/prsht.h b/include/prsht.h
index 27e43c8..0830757 100644
--- a/include/prsht.h
+++ b/include/prsht.h
@@ -266,7 +266,7 @@ DECL_WINELIB_TYPE_AW(LPFNPSPCALLBACK)
 #define PSH_WIZARD97_NEW        0x01000000 /* for IE >= 5 */
 #define PSH_NOCONTEXTHELP       0x02000000
 #ifndef __WINESRC__
-# if _WIN32_IE < 0x0500
+# if defined(_WIN32_IE) && (_WIN32_IE < 0x0500)
 #  define PSH_WIZARD97          PSH_WIZARD97_OLD
 # else
 #  define PSH_WIZARD97          PSH_WIZARD97_NEW