headers/_mingw,ddk: Undefine `MINGW_HAS_DDK_H`

No code is known to check for this macro.

Signed-off-by: LIU Hao <lh_mouse@126.com>

mingw-w64-headers/configure.ac

diff --git a/mingw-w64-headers/configure.ac b/mingw-w64-headers/configure.ac
index 186e989..f880240 100644
--- a/mingw-w64-headers/configure.ac
+++ b/mingw-w64-headers/configure.ac
@@ -109,12 +109,8 @@
 
 AS_VAR_IF([enable_ddk],[yes],[
     DDKHEAD_LIST=$srcdir/ddk/include/ddk/*.h
-    MINGW_HAS_DDK=1
-  ],[
-    MINGW_HAS_DDK=0
-  ])
+  ],[])
 AC_SUBST([DDKHEAD_LIST])
-AC_SUBST([MINGW_HAS_DDK])
 
 AC_MSG_CHECKING([if installing idl files is enabled])
 AC_ARG_ENABLE([idl],

mingw-w64-headers/crt/_mingw.h.in

diff --git a/mingw-w64-headers/crt/_mingw.h.in b/mingw-w64-headers/crt/_mingw.h.in
index 4aa92f4..3e0d544 100644
--- a/mingw-w64-headers/crt/_mingw.h.in
+++ b/mingw-w64-headers/crt/_mingw.h.in
@@ -676,8 +676,4 @@
 #define __STDC_SECURE_LIB__ 200411L
 #define __GOT_SECURE_LIB__ __STDC_SECURE_LIB__
 
-#if @MINGW_HAS_DDK@
-#define MINGW_HAS_DDK_H 1
-#endif
-
 #endif /* MINGW_SDK_INIT */

mingw-w64-headers/ddk/readme.txt

diff --git a/mingw-w64-headers/ddk/readme.txt b/mingw-w64-headers/ddk/readme.txt
index 9dea9ee..3c7bd82 100644
--- a/mingw-w64-headers/ddk/readme.txt
+++ b/mingw-w64-headers/ddk/readme.txt
@@ -1,9 +1,6 @@
 DDK sdk for x86 and x64 platforms.
 ----------------------------------
 
-You can check for existance of this optional package by verifying
-the definition of the macro MINGW_HAS_DDK_H.
-
 The DDK headers are from the ReactOS project, from their svn repo
 svn://svn.reactos.org/reactos/trunk/reactos/include/ddk/