diff -rupN gdal-3.1.2-fedora/frmts/jpeg2000/jpeg2000dataset.cpp gdal-3.1.2-fedora-new/frmts/jpeg2000/jpeg2000dataset.cpp
--- gdal-3.1.2-fedora/frmts/jpeg2000/jpeg2000dataset.cpp	2020-07-07 13:46:27.000000000 +0200
+++ gdal-3.1.2-fedora-new/frmts/jpeg2000/jpeg2000dataset.cpp	2020-07-22 12:26:50.419482813 +0200
@@ -595,7 +595,7 @@ GDALDataset *JPEG2000Dataset::Open( GDAL
 
 {
     int         iFormat;
-    char        *pszFormatName = nullptr;
+    const char        *pszFormatName = nullptr;
 
     if (!Identify(poOpenInfo))
         return nullptr;
diff -rupN gdal-3.1.2-fedora/frmts/jpeg2000/jpeg2000_vsil_io.cpp gdal-3.1.2-fedora-new/frmts/jpeg2000/jpeg2000_vsil_io.cpp
--- gdal-3.1.2-fedora/frmts/jpeg2000/jpeg2000_vsil_io.cpp	2020-07-07 13:46:27.000000000 +0200
+++ gdal-3.1.2-fedora-new/frmts/jpeg2000/jpeg2000_vsil_io.cpp	2020-07-22 13:29:02.017426423 +0200
@@ -94,13 +94,13 @@ typedef struct {
 * File stream object.
 \******************************************************************************/
 
-static int JPEG2000_VSIL_read(jas_stream_obj_t *obj, char *buf, int cnt)
+static int JPEG2000_VSIL_read(jas_stream_obj_t *obj, char *buf, unsigned int cnt)
 {
     jas_stream_VSIFL_t *fileobj = JAS_CAST(jas_stream_VSIFL_t *, obj);
     return static_cast<int>(VSIFReadL(buf, 1, cnt, fileobj->fp));
 }
 
-static int JPEG2000_VSIL_write(jas_stream_obj_t *obj, char *buf, int cnt)
+static int JPEG2000_VSIL_write(jas_stream_obj_t *obj, char *buf, unsigned int cnt)
 {
     jas_stream_VSIFL_t *fileobj = JAS_CAST(jas_stream_VSIFL_t *, obj);
     return static_cast<int>(VSIFWriteL(buf, 1, cnt, fileobj->fp));