make the headers for support code more C++ friendly

tests/chardata.h

@@ -0,0 +1,40 @@
+/* chardata.h
+
+   Interface to some helper routines used to accumulate and check text
+   and attribute content.
+*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef XML_CHARDATA_H
+#define XML_CHARDATA_H 1
+
+#ifndef XML_VERSION
+#include "expat.h"                      /* need XML_Char */
+#endif
+
+
+typedef struct {
+    int count;                          /* # of chars, < 0 if not set */
+    XML_Char data[1024];
+} CharData;
+
+
+void CharData_Init(CharData *storage);
+
+void CharData_AppendString(CharData *storage, const char *s);
+
+void CharData_AppendXMLChars(CharData *storage, const XML_Char *s, int len);
+
+int CharData_CheckString(CharData *storage, const char *s);
+
+int CharData_CheckXMLChars(CharData *storage, const XML_Char *s);
+
+
+#endif  /* XML_CHARDATA_H */
+
+#ifdef __cplusplus
+}
+#endif