From 3d3bd4e77e71e96699589d642d8c6e903df6219b Mon Sep 17 00:00:00 2001
From: Mark Jansen <mark.jansen@reactos.org>
Date: Sun, 23 Sep 2018 19:28:09 +0200
Subject: [PATCH] [WIN32K] Work around GCC builds inventing dead keys.
 CORE-14948

---
 win32ss/user/ntuser/keyboard.c | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/win32ss/user/ntuser/keyboard.c b/win32ss/user/ntuser/keyboard.c
index 6167f9d6fff..f72e275cf2d 100644
--- a/win32ss/user/ntuser/keyboard.c
+++ b/win32ss/user/ntuser/keyboard.c
@@ -467,18 +467,31 @@ IntToUnicodeEx(UINT wVirtKey,
         WCHAR wchFirst, wchSecond;
         TRACE("Previous dead char: %lc (%x)\n", wchDead, wchDead);
 
-        for (i = 0; pKbdTbl->pDeadKey[i].dwBoth; i++)
+        if (pKbdTbl->pDeadKey)
         {
-            wchFirst = pKbdTbl->pDeadKey[i].dwBoth >> 16;
-            wchSecond = pKbdTbl->pDeadKey[i].dwBoth & 0xFFFF;
-            if (wchFirst == wchDead && wchSecond == wchTranslatedChar)
+            for (i = 0; pKbdTbl->pDeadKey[i].dwBoth; i++)
             {
-                wchTranslatedChar = pKbdTbl->pDeadKey[i].wchComposed;
-                wchDead = 0;
-                bDead = FALSE;
-                break;
+                wchFirst = pKbdTbl->pDeadKey[i].dwBoth >> 16;
+                wchSecond = pKbdTbl->pDeadKey[i].dwBoth & 0xFFFF;
+                if (wchFirst == wchDead && wchSecond == wchTranslatedChar)
+                {
+                    wchTranslatedChar = pKbdTbl->pDeadKey[i].wchComposed;
+                    wchDead = 0;
+                    bDead = FALSE;
+                    break;
+                }
             }
         }
+        else
+        {
+#if defined(__GNUC__)
+            if (wchDead == 0x8000)
+            {
+                ERR("GCC is inventing bits, ignoring fake dead key\n");
+                wchDead = 0;
+            }
+#endif
+        }
 
         TRACE("Final char: %lc (%x)\n", wchTranslatedChar, wchTranslatedChar);
     }