Avoid duplicate const specifier compiler warnings

The original code is perfectly valid standard C. However, some compilers (especially GCC) complain about duplicate const specifiers anyway.
At this point we cave in as there doesn't seem to be any efforts to fix this problem by the corresponding compiler vendors.

uGFX v3 will no longer suffer from this problem as the driver interface works differently in this area.

drivers/multiple/Win32/gdisp_lld_Win32.c

@@ -99,7 +99,11 @@
 	static gBool Win32MouseInit(GMouse *m, unsigned driverinstance);
 	static gBool Win32MouseRead(GMouse *m, GMouseReading *prd);
 
-	const GMouseVMT const GMOUSE_DRIVER_VMT[1] = {{
+	/**
+	 * This should be: const GMouseVMT const GMOUSE_DRIVER_VMT[1] = {{
+	 * However, some major compilers complain about the duplicate const specifier even though this is perfectly valid standard C.
+	 */
+	const GMouseVMT GMOUSE_DRIVER_VMT[1] = {{
 		{
 			GDRIVER_TYPE_MOUSE,
 			GMOUSE_VFLG_NOPOLL|GMOUSE_VFLG_DYNAMICONLY,
@@ -885,7 +889,7 @@ LLDSPEC gBool gdisp_lld_init(GDisplay *g) {
 	// Create the associated mouse
 	#if GFX_USE_GINPUT && GINPUT_NEED_MOUSE
 		priv->mouseenabled = hWndParent ? gFalse : gTrue;
-		priv->mouse = (GMouse *)gdriverRegister((const GDriverVMT const *)GMOUSE_DRIVER_VMT, g);
+		priv->mouse = (GMouse *)gdriverRegister((const GDriverVMT*)GMOUSE_DRIVER_VMT, g);
 	#endif
 
 	sprintf(buf, APP_NAME " - %u", g->systemdisplay+1);

src/gdisp/gdisp.c

@@ -574,7 +574,7 @@ void _gdispInit(void)
 	#elif GDISP_TOTAL_DISPLAYS > 1
 		{
 			unsigned	i;
-			extern const GDISPVMT const		GDISPVMT_OnlyOne[1];
+			extern const GDISPVMT GDISPVMT_OnlyOne[1];
 
 			if (!(GDISPVMT_OnlyOne->d.flags & GDISP_VFLG_DYNAMICONLY)) {
 				for(i = 0; i < GDISP_TOTAL_DISPLAYS; i++)
@@ -583,7 +583,7 @@ void _gdispInit(void)
 		}
 	#else
 		{
-			extern const GDISPVMT const		GDISPVMT_OnlyOne[1];
+			extern const GDISPVMT GDISPVMT_OnlyOne[1];
 
 			if (!(GDISPVMT_OnlyOne->d.flags & GDISP_VFLG_DYNAMICONLY))
 				gdriverRegister(&GDISPVMT_OnlyOne->d, 0);

src/gdisp/gdisp_driver.h

@@ -732,7 +732,11 @@ typedef struct GDISPVMT {
 	#endif
 
 	// Build the VMT
-	const GDISPVMT const GDISP_DRIVER_VMT[1] = {{
+	/*
+	 * This should read: const GDISPVMT const GDISP_DRIVER_VMT[1] = {{
+	 * However, some major C compilers complain about duplicate const specifiers although this is perfectly valid standard C.
+	 */
+	const GDISPVMT GDISP_DRIVER_VMT[1] = {{
 		{ GDRIVER_TYPE_DISPLAY, 0, sizeof(GDisplay), _gdispInitDriver, _gdispPostInitDriver, _gdispDeInitDriver },
 		gdisp_lld_init,
 		#if GDISP_HARDWARE_DEINIT

src/gdriver/gdriver.h

@@ -86,8 +86,16 @@ typedef struct GDriverVMT {
  * 				const GDriverVMT const * mylist = { DRIVER_LIST };
  * 				</code>
  *
+ * @note This could be one single typedef. However, some major compilers complain about duplicate const specifiers even though this is perfectly
+ *       valid standard C. As this problem has become worse over time we opt for splitting this into two separate typedefs to prevent these
+ *       compilers from throwing warnings.
+ *       The single typedef would look like this:
+ *       <code>
+ *           typedef const struct GDriverVMT const GDriverVMTList[1];
+ *       </code>
  */
-typedef const struct GDriverVMT const	GDriverVMTList[1];
+typedef const struct GDriverVMT ConstGDriverVMT;
+typedef ConstGDriverVMT const GDriverVMTList[1];
 
 /*===========================================================================*/
 /* External declarations.                                                    */

src/gfile/gfile.c

@@ -36,8 +36,11 @@
 /**
  * The order of the file-systems below determines the order
  * that they are searched to find a file.
+ *
+ * This should read: static const GFILEVMT const * FsArray[] = {
+ * However, some major C compilers complain about duplicate const specifiers although this is perfectly valid standard C.
  */
-static const GFILEVMT const * FsArray[] = {
+static const GFILEVMT* FsArray[] = {
 	#if GFILE_NEED_USERFS
 		&FsUSERVMT,
 	#endif

src/gfile/gfile_fs_rom.c

@@ -34,7 +34,12 @@ typedef struct ROMFS_DIRENTRY {
 
 #define ROMFS_DIRENTRY_HEAD		0
 #include "romfs_files.h"
-static const ROMFS_DIRENTRY const *FsROMHead = ROMFS_DIRENTRY_HEAD;
+
+/*
+ * This should be: static const ROMFS_DIRENTRY const *FsROMHead = ROMFS_DIRENTRY_HEAD;
+ * However, some major compilers complain about the duplicate const specifier even though this is perfectly valid standard C.
+ */
+static const ROMFS_DIRENTRY *FsROMHead = ROMFS_DIRENTRY_HEAD;
 
 typedef struct ROMFileList {
 	gfileList				fl;

src/ginput/ginput_mouse.c

@@ -663,7 +663,11 @@ void _gmouseInit(void) {
 	// One and only one mouse
 	#else
 		{
-			extern const GMouseVMT const GMOUSEVMT_OnlyOne[1];
+			/*
+			 * This should be: extern const GMouseVMT const GMOUSEVMT_OnlyOne[1];
+			 * However, some major compilers complain about the duplicate const specifier even though this is perfectly valid standard C.
+			 */
+			extern const GMouseVMT GMOUSEVMT_OnlyOne[1];
 
             if (!(GMOUSEVMT_OnlyOne->d.flags & GMOUSE_VFLG_DYNAMICONLY))
 					gdriverRegister(&GMOUSEVMT_OnlyOne->d, GDISP);