Add XML_DEPRECATED macro

__attribute__((deprecated)) is available since at least GCC 3.1, so an
exact version check is probably unnecessary.

include/libxml/xmlversion.h.in

@@ -456,6 +456,15 @@
 # define LIBXML_ATTR_FORMAT(fmt,args)
 #endif
 
+#ifndef XML_DEPRECATED
+#  ifdef IN_LIBXML
+#    define XML_DEPRECATED
+#  else
+/* Available since at least GCC 3.1 */
+#    define XML_DEPRECATED __attribute__((deprecated))
+#  endif
+#endif
+
 #else /* ! __GNUC__ */
 /**
  * ATTRIBUTE_UNUSED:
@@ -475,6 +484,15 @@
  * Macro used to indicate to GCC the parameter are printf like
  */
 #define LIBXML_ATTR_FORMAT(fmt,args)
+/**
+ * XML_DEPRECATED:
+ *
+ * Macro used to indicate that a function, variable, type or struct member
+ * is deprecated.
+ */
+#ifndef XML_DEPRECATED
+#define XML_DEPRECATED
+#endif
 #endif /* __GNUC__ */
 
 #ifdef __cplusplus

testapi.c

@@ -8,6 +8,9 @@
  * daniel@veillard.com
  */
+/* Disable deprecation warnings */
+#define XML_DEPRECATED
+
 #include "libxml.h"
 #include <stdio.h>