https://bugs.gentoo.org/883707
diff --git a/imgJPEG.c b/imgJPEG.c
index cb62e40..4ca80b5 100644
--- a/imgJPEG.c
+++ b/imgJPEG.c
@@ -118,7 +118,7 @@ static int	ChnWriteJPEG _ANSI_ARGS_((Tcl_Interp *interp,
 		    char *fileName, Tcl_Obj *format,
 		    Tk_PhotoImageBlock *blockPtr));
 static int	StringWriteJPEG _ANSI_ARGS_((Tcl_Interp *interp,
-		    Tcl_DString *dataPtr, Tcl_Obj *format,
+		    Tcl_Obj *format,
 		    Tk_PhotoImageBlock *blockPtr));
 
 Tk_PhotoImageFormat imgFmtJPEG = {
@@ -970,7 +970,7 @@ CommonReadJPEG(interp, cinfo, format, imageHandle, destX, destY,
     int srcX, srcY;		/* Coordinates of top-left pixel to be used
 				 * in image being read. */
 {
-    static char *jpegReadOptions[] = {"-fast", "-grayscale", NULL};
+    static const char *jpegReadOptions[] = {"-fast", "-grayscale", NULL};
     int fileWidth, fileHeight, stopY, curY, outY, outWidth, outHeight;
     myblock bl;
 #define block bl.ck
@@ -1262,7 +1262,7 @@ CommonWriteJPEG(interp, cinfo, format, blockPtr)
     Tcl_Obj *format;
     Tk_PhotoImageBlock *blockPtr;
 {
-    static char *jpegWriteOptions[] = {"-grayscale", "-optimize",
+    static const char *jpegWriteOptions[] = {"-grayscale", "-optimize",
 	"-progressive", "-quality", "-smooth", NULL};
     JSAMPROW row_pointer[1];	/* pointer to original data scanlines */
     JSAMPARRAY buffer;		/* Intermediate row buffer */