Add MariaDB Connector/C as a built-in alternative (v3.2.3).

vendor/MDBC/win-iconv/iconv.h

@@ -0,0 +1,14 @@
+#ifndef _LIBICONV_H
+#define _LIBICONV_H
+#include <stddef.h>
+#ifdef __cplusplus
+extern "C" {
+#endif
+typedef void* iconv_t;
+iconv_t iconv_open(const char *tocode, const char *fromcode);
+int iconv_close(iconv_t cd);
+size_t iconv(iconv_t cd, const char **inbuf, size_t *inbytesleft, char **outbuf, size_t *outbytesleft);
+#ifdef __cplusplus
+}
+#endif
+#endif//_LIBICONV_H