Removed some of the XXX_reg macros now that we are using the standard
CONTEXT86 structure everywhere.

diff --git a/dlls/ntdll/rtl.c b/dlls/ntdll/rtl.c
index 053d690..79c4fe0 100644
--- a/dlls/ntdll/rtl.c
+++ b/dlls/ntdll/rtl.c
@@ -363,11 +363,11 @@
  */
 void WINAPI NTDLL_chkstk( CONTEXT86 *context )
 {
-    ESP_reg(context) -= EAX_reg(context);
+    context->Esp -= context->Eax;
 }
 void WINAPI NTDLL_alloca_probe( CONTEXT86 *context )
 {
-    ESP_reg(context) -= EAX_reg(context);
+    context->Esp -= context->Eax;
 }
 
 /******************************************************************************