[libxml2] Always define LIBXML_THREAD_ENABLED when enabled

[Nick Wellnhofer <nwellnhof src gnome org>]

commit cf68fe3d505dd3f7525ccc28c90f87432a747aa4
Author: Michael Haubenwallner <michael haubenwallner ssi-schaefer com>
Date:   Wed Feb 27 15:00:14 2019 +0100

    Always define LIBXML_THREAD_ENABLED when enabled
    
    When libxml2 is compiled with threads enabled, have the header file
    define LIBXML_THREAD_ENABLED even if the subsequent application by
    itself does not enable threads.  Otherwise, the application would see
    the unthreaded API functions, but these are not exported (where it does
    make a difference, like on Win32 based platforms).

 include/libxml/xmlversion.h.in | 3 ---
 1 file changed, 3 deletions(-)
---
diff --git a/include/libxml/xmlversion.h.in b/include/libxml/xmlversion.h.in
index d10f9754..5ba64f23 100644
--- a/include/libxml/xmlversion.h.in
+++ b/include/libxml/xmlversion.h.in
@@ -91,11 +91,8 @@ XMLPUBFUN void XMLCALL xmlCheckVersion(int version);
  * Whether the thread support is configured in
  */
 #if @WITH_THREADS@
-#if defined(_REENTRANT) || defined(__MT__) || \
-    (defined(_POSIX_C_SOURCE) && (_POSIX_C_SOURCE - 0 >= 199506L))
 #define LIBXML_THREAD_ENABLED
 #endif
-#endif
 
 /**
  * LIBXML_THREAD_ALLOC_ENABLED: