diff -rupN libspatialite-5.1.0/src/gaiaaux/gg_utf8.c libspatialite-5.1.0-new/src/gaiaaux/gg_utf8.c
--- libspatialite-5.1.0/src/gaiaaux/gg_utf8.c	2023-08-04 09:51:40.000000000 +0200
+++ libspatialite-5.1.0-new/src/gaiaaux/gg_utf8.c	2024-03-05 23:09:38.938054342 +0100
@@ -130,7 +130,12 @@ gaiaConvertCharset (char **buf, const ch
     pBuf = *buf;
     utf8buf = sqlite3_malloc (utf8len);
     pUtf8buf = utf8buf;
-    if (iconv (cvt, &pBuf, &len, &pUtf8buf, &utf8len) == (size_t) (-1))
+#if defined(__MINGW32__)
+    WINICONV_CONST char ** ppBuf = (WINICONV_CONST char**)&pBuf;
+#else
+    char ** ppBuf = &pBuf;
+#endif
+    if (iconv (cvt, ppBuf, &len, &pUtf8buf, &utf8len) == (size_t) (-1))
 	goto error;
     utf8buf[maxlen - utf8len] = '\0';
     sqlite3_free (*buf);
@@ -188,7 +193,12 @@ gaiaConvertToUTF8 (void *cvtCS, const ch
     utf8len = maxlen;
     pBuf = (char *) buf;
     pUtf8buf = utf8buf;
-    if (iconv (cvtCS, &pBuf, &len, &pUtf8buf, &utf8len) == (size_t) (-1))
+#if defined(__MINGW32__)
+    WINICONV_CONST char ** ppBuf = (WINICONV_CONST char**)&pBuf;
+#else
+    char ** ppBuf = &pBuf;
+#endif
+    if (iconv (cvtCS, ppBuf, &len, &pUtf8buf, &utf8len) == (size_t) (-1))
       {
 	  free (utf8buf);
 	  *err = 1;
@@ -224,7 +234,12 @@ url_toUtf8 (const char *url, const char
     utf8len = maxlen;
     utf8buf = malloc (maxlen);
     pUtf8buf = utf8buf;
-    if (iconv (cvt, &pBuf, &len, &pUtf8buf, &utf8len) == (size_t) (-1))
+#if defined(__MINGW32__)
+    WINICONV_CONST char ** ppBuf = (WINICONV_CONST char**)&pBuf;
+#else
+    char ** ppBuf = &pBuf;
+#endif
+    if (iconv (cvt, ppBuf, &len, &pUtf8buf, &utf8len) == (size_t) (-1))
 	goto error;
     utf8buf[maxlen - utf8len] = '\0';
     iconv_close (cvt);
@@ -252,6 +267,12 @@ url_fromUtf8 (const char *url, const cha
 #else /* not WIN32 */
     char *pBuf = (char *) url;
 #endif
+#if defined(__MINGW32__)
+    WINICONV_CONST char ** ppBuf = (WINICONV_CONST char**)&pBuf;
+#else
+    char ** ppBuf = &pBuf;
+#endif
+
 
     if (url == NULL || out_charset == NULL)
 	return NULL;
@@ -263,7 +284,7 @@ url_fromUtf8 (const char *url, const cha
     utf8len = maxlen;
     utf8buf = malloc (maxlen);
     pUtf8buf = utf8buf;
-    if (iconv (cvt, &pBuf, &len, &pUtf8buf, &utf8len) == (size_t) (-1))
+    if (iconv (cvt, ppBuf, &len, &pUtf8buf, &utf8len) == (size_t) (-1))
 	goto error;
     utf8buf[maxlen - utf8len] = '\0';
     iconv_close (cvt);
diff -rupN libspatialite-5.1.0/src/gaiageo/gg_shape.c libspatialite-5.1.0-new/src/gaiageo/gg_shape.c
--- libspatialite-5.1.0/src/gaiageo/gg_shape.c	2023-08-04 09:51:40.000000000 +0200
+++ libspatialite-5.1.0-new/src/gaiageo/gg_shape.c	2024-03-05 23:21:43.191027073 +0100
@@ -694,8 +694,13 @@ gaiaOpenShpRead (gaiaShapefilePtr shp, c
 	  utf8len = 2048;
 	  pBuf = (char *) field_name;
 	  pUtf8buf = utf8buf;
+#if defined(__MINGW32__)
+	  WINICONV_CONST char ** ppBuf = (WINICONV_CONST char**)&pBuf;
+#else
+	  char ** ppBuf = &pBuf;
+#endif
 	  if (iconv
-	      ((iconv_t) (shp->IconvObj), &pBuf, &len, &pUtf8buf,
+	      ((iconv_t) (shp->IconvObj), ppBuf, &len, &pUtf8buf,
 	       &utf8len) == (size_t) (-1))
 	    {
 		spatialite_e
@@ -1178,8 +1183,13 @@ gaiaOpenShpWriteEx (gaiaShapefilePtr shp
 	  utf8len = 2048;
 	  pBuf = buf;
 	  pUtf8buf = utf8buf;
+#if defined(__MINGW32__)
+	  WINICONV_CONST char ** ppBuf = (WINICONV_CONST char**)&pBuf;
+#else
+	  char ** ppBuf = &pBuf;
+#endif
 	  if (iconv
-	      ((iconv_t) (shp->IconvObj), &pBuf, &len, &pUtf8buf,
+	      ((iconv_t) (shp->IconvObj), ppBuf, &len, &pUtf8buf,
 	       &utf8len) == (size_t) (-1))
 	      sprintf (buf, "FLD#%d", defaultId++);
 	  else
@@ -1546,8 +1556,13 @@ parseDbfField (unsigned char *buf_dbf, v
 		utf8len = 2048;
 		pBuf = (char *) buf;
 		pUtf8buf = utf8buf;
+#if defined(__MINGW32__)
+		WINICONV_CONST char ** ppBuf = (WINICONV_CONST char**)&pBuf;
+#else
+		char ** ppBuf = &pBuf;
+#endif
 		if (iconv
-		    ((iconv_t) (iconv_obj), &pBuf, &len, &pUtf8buf,
+		    ((iconv_t) (iconv_obj), ppBuf, &len, &pUtf8buf,
 		     &utf8len) == (size_t) (-1))
 		    return 0;
 		memcpy (buf, utf8buf, 2048 - utf8len);
@@ -3029,8 +3044,13 @@ gaiaWriteShpEntity (gaiaShapefilePtr shp
 			    utf8len = 2048;
 			    pBuf = dynbuf;
 			    pUtf8buf = utf8buf;
+#if defined(__MINGW32__)
+			    WINICONV_CONST char ** ppBuf = (WINICONV_CONST char**)&pBuf;
+#else
+			    char ** ppBuf = &pBuf;
+#endif
 			    if (iconv
-				((iconv_t) (shp->IconvObj), &pBuf, &len,
+				((iconv_t) (shp->IconvObj), ppBuf, &len,
 				 &pUtf8buf, &utf8len) == (size_t) (-1))
 			      {
 				  spatialite_e
@@ -5115,8 +5135,13 @@ gaiaOpenDbfRead (gaiaDbfPtr dbf, const c
 	  utf8len = 2048;
 	  pBuf = (char *) field_name;
 	  pUtf8buf = utf8buf;
+#if defined(__MINGW32__)
+	  WINICONV_CONST char ** ppBuf = (WINICONV_CONST char**)&pBuf;
+#else
+	  char ** ppBuf = &pBuf;
+#endif
 	  if (iconv
-	      ((iconv_t) (dbf->IconvObj), &pBuf, &len, &pUtf8buf,
+	      ((iconv_t) (dbf->IconvObj), ppBuf, &len, &pUtf8buf,
 	       &utf8len) == (size_t) (-1))
 	    {
 		spatialite_e
@@ -5311,8 +5336,13 @@ gaiaOpenDbfWriteEx (gaiaDbfPtr dbf, cons
 	  utf8len = 2048;
 	  pBuf = buf;
 	  pUtf8buf = utf8buf;
+#if defined(__MINGW32__)
+	  WINICONV_CONST char ** ppBuf = (WINICONV_CONST char**)&pBuf;
+#else
+	  char ** ppBuf = &pBuf;
+#endif
 	  if (iconv
-	      ((iconv_t) (dbf->IconvObj), &pBuf, &len, &pUtf8buf,
+	      ((iconv_t) (dbf->IconvObj), ppBuf, &len, &pUtf8buf,
 	       &utf8len) == (size_t) (-1))
 	      sprintf (buf, "FLD#%d", defaultId++);
 	  else
@@ -5432,8 +5462,13 @@ gaiaWriteDbfEntity (gaiaDbfPtr dbf, gaia
 			    utf8len = 2048;
 			    pBuf = dynbuf;
 			    pUtf8buf = utf8buf;
+#if defined(__MINGW32__)
+			    WINICONV_CONST char ** ppBuf = (WINICONV_CONST char**)&pBuf;
+#else
+			    char ** ppBuf = &pBuf;
+#endif
 			    if (iconv
-				((iconv_t) (dbf->IconvObj), &pBuf, &len,
+				((iconv_t) (dbf->IconvObj), ppBuf, &len,
 				 &pUtf8buf, &utf8len) == (size_t) (-1))
 			      {
 				  spatialite_e