diff --git a/configure b/configure
index 799d1755e..efca355fb 100755
--- a/configure
+++ b/configure
@@ -23374,7 +23374,7 @@ $as_echo "#define SDL_FILESYSTEM_NACL 1" >>confdefs.h
 esac
 
 CheckWarnAll
-#CheckWarnShadow
+CheckWarnShadow
 
 # Verify that we have all the platform specific files we need
 
diff --git a/configure.in b/configure.in
index 2ea381830..e0dfac1d2 100644
--- a/configure.in
+++ b/configure.in
@@ -3238,7 +3238,7 @@ esac
 
 dnl Do this on all platforms, after everything else.
 CheckWarnAll
-#CheckWarnShadow
+CheckWarnShadow
 
 # Verify that we have all the platform specific files we need
 
diff --git a/src/thread/SDL_thread.c b/src/thread/SDL_thread.c
index 6cd933311..3724f4f3c 100644
--- a/src/thread/SDL_thread.c
+++ b/src/thread/SDL_thread.c
@@ -442,10 +442,10 @@ SDL_DetachThread(SDL_Thread * thread)
         SDL_SYS_DetachThread(thread);
     } else {
         /* all other states are pretty final, see where we landed. */
-        const int state = SDL_AtomicGet(&thread->state);
-        if ((state == SDL_THREAD_STATE_DETACHED) || (state == SDL_THREAD_STATE_CLEANED)) {
+        const int thread_state = SDL_AtomicGet(&thread->state);
+        if ((thread_state == SDL_THREAD_STATE_DETACHED) || (thread_state == SDL_THREAD_STATE_CLEANED)) {
             return;  /* already detached (you shouldn't call this twice!) */
-        } else if (state == SDL_THREAD_STATE_ZOMBIE) {
+        } else if (thread_state == SDL_THREAD_STATE_ZOMBIE) {
             SDL_WaitThread(thread, NULL);  /* already done, clean it up. */
         } else {
             SDL_assert(0 && "Unexpected thread state");
diff --git a/src/video/SDL_RLEaccel.c b/src/video/SDL_RLEaccel.c
index a464dec39..58293677f 100644
--- a/src/video/SDL_RLEaccel.c
+++ b/src/video/SDL_RLEaccel.c
@@ -376,10 +376,10 @@
  * right. Top clipping has already been taken care of.
  */
 static void
-RLEClipBlit(int w, Uint8 * srcbuf, SDL_Surface * dst,
+RLEClipBlit(int w, Uint8 * srcbuf, SDL_Surface * surf_dst,
             Uint8 * dstbuf, SDL_Rect * srcrect, unsigned alpha)
 {
-    SDL_PixelFormat *fmt = dst->format;
+    SDL_PixelFormat *fmt = surf_dst->format;
 
 #define RLECLIPBLIT(bpp, Type, do_blit)                    \
     do {                                   \
@@ -418,7 +418,7 @@ RLEClipBlit(int w, Uint8 * srcbuf, SDL_Surface * dst,
         break;                             \
         if(ofs == w) {                         \
         ofs = 0;                           \
-        dstbuf += dst->pitch;                      \
+        dstbuf += surf_dst->pitch;                      \
         if(!--linecount)                       \
             break;                         \
         }                                  \
@@ -434,18 +434,18 @@ RLEClipBlit(int w, Uint8 * srcbuf, SDL_Surface * dst,
 
 /* blit a colorkeyed RLE surface */
 int
-SDL_RLEBlit(SDL_Surface * src, SDL_Rect * srcrect,
-            SDL_Surface * dst, SDL_Rect * dstrect)
+SDL_RLEBlit(SDL_Surface * surf_src, SDL_Rect * srcrect,
+            SDL_Surface * surf_dst, SDL_Rect * dstrect)
 {
     Uint8 *dstbuf;
     Uint8 *srcbuf;
     int x, y;
-    int w = src->w;
+    int w = surf_src->w;
     unsigned alpha;
 
     /* Lock the destination if necessary */
-    if (SDL_MUSTLOCK(dst)) {
-        if (SDL_LockSurface(dst) < 0) {
+    if (SDL_MUSTLOCK(surf_dst)) {
+        if (SDL_LockSurface(surf_dst) < 0) {
             return (-1);
         }
     }
@@ -453,9 +453,9 @@ SDL_RLEBlit(SDL_Surface * src, SDL_Rect * srcrect,
     /* Set up the source and destination pointers */
     x = dstrect->x;
     y = dstrect->y;
-    dstbuf = (Uint8 *) dst->pixels
-        + y * dst->pitch + x * src->format->BytesPerPixel;
-    srcbuf = (Uint8 *) src->map->data;
+    dstbuf = (Uint8 *) surf_dst->pixels
+        + y * surf_dst->pitch + x * surf_src->format->BytesPerPixel;
+    srcbuf = (Uint8 *) surf_src->map->data;
 
     {
         /* skip lines at the top if necessary */
@@ -481,7 +481,7 @@ SDL_RLEBlit(SDL_Surface * src, SDL_Rect * srcrect,
             }               \
         }
 
-            switch (src->format->BytesPerPixel) {
+            switch (surf_src->format->BytesPerPixel) {
             case 1:
                 RLESKIP(1, Uint8);
                 break;
@@ -501,12 +501,12 @@ SDL_RLEBlit(SDL_Surface * src, SDL_Rect * srcrect,
         }
     }
 
-    alpha = src->map->info.a;
+    alpha = surf_src->map->info.a;
     /* if left or right edge clipping needed, call clip blit */
-    if (srcrect->x || srcrect->w != src->w) {
-        RLEClipBlit(w, srcbuf, dst, dstbuf, srcrect, alpha);
+    if (srcrect->x || srcrect->w != surf_src->w) {
+        RLEClipBlit(w, srcbuf, surf_dst, dstbuf, srcrect, alpha);
     } else {
-        SDL_PixelFormat *fmt = src->format;
+        SDL_PixelFormat *fmt = surf_src->format;
 
 #define RLEBLIT(bpp, Type, do_blit)                       \
         do {                                  \
@@ -525,7 +525,7 @@ SDL_RLEBlit(SDL_Surface * src, SDL_Rect * srcrect,
             break;                            \
             if(ofs == w) {                        \
             ofs = 0;                          \
-            dstbuf += dst->pitch;                     \
+            dstbuf += surf_dst->pitch;                     \
             if(!--linecount)                      \
                 break;                        \
             }                                 \
@@ -539,8 +539,8 @@ SDL_RLEBlit(SDL_Surface * src, SDL_Rect * srcrect,
 
   done:
     /* Unlock the destination if necessary */
-    if (SDL_MUSTLOCK(dst)) {
-        SDL_UnlockSurface(dst);
+    if (SDL_MUSTLOCK(surf_dst)) {
+        SDL_UnlockSurface(surf_dst);
     }
     return (0);
 }
@@ -620,10 +620,10 @@ typedef struct
 
 /* blit a pixel-alpha RLE surface clipped at the right and/or left edges */
 static void
-RLEAlphaClipBlit(int w, Uint8 * srcbuf, SDL_Surface * dst,
+RLEAlphaClipBlit(int w, Uint8 * srcbuf, SDL_Surface * surf_dst,
                  Uint8 * dstbuf, SDL_Rect * srcrect)
 {
-    SDL_PixelFormat *df = dst->format;
+    SDL_PixelFormat *df = surf_dst->format;
     /*
      * clipped blitter: Ptype is the destination pixel type,
      * Ctype the translucent count type, and do_blend the macro
@@ -693,7 +693,7 @@ RLEAlphaClipBlit(int w, Uint8 * srcbuf, SDL_Surface * dst,
             ofs += run;                       \
         }                             \
         } while(ofs < w);                         \
-        dstbuf += dst->pitch;                     \
+        dstbuf += surf_dst->pitch;                     \
     } while(--linecount);                         \
     } while(0)
 
@@ -712,25 +712,25 @@ RLEAlphaClipBlit(int w, Uint8 * srcbuf, SDL_Surface * dst,
 
 /* blit a pixel-alpha RLE surface */
 int
-SDL_RLEAlphaBlit(SDL_Surface * src, SDL_Rect * srcrect,
-                 SDL_Surface * dst, SDL_Rect * dstrect)
+SDL_RLEAlphaBlit(SDL_Surface * surf_src, SDL_Rect * srcrect,
+                 SDL_Surface * surf_dst, SDL_Rect * dstrect)
 {
     int x, y;
-    int w = src->w;
+    int w = surf_src->w;
     Uint8 *srcbuf, *dstbuf;
-    SDL_PixelFormat *df = dst->format;
+    SDL_PixelFormat *df = surf_dst->format;
 
     /* Lock the destination if necessary */
-    if (SDL_MUSTLOCK(dst)) {
-        if (SDL_LockSurface(dst) < 0) {
+    if (SDL_MUSTLOCK(surf_dst)) {
+        if (SDL_LockSurface(surf_dst) < 0) {
             return -1;
         }
     }
 
     x = dstrect->x;
     y = dstrect->y;
-    dstbuf = (Uint8 *) dst->pixels + y * dst->pitch + x * df->BytesPerPixel;
-    srcbuf = (Uint8 *) src->map->data + sizeof(RLEDestFormat);
+    dstbuf = (Uint8 *) surf_dst->pixels + y * surf_dst->pitch + x * df->BytesPerPixel;
+    srcbuf = (Uint8 *) surf_src->map->data + sizeof(RLEDestFormat);
 
     {
         /* skip lines at the top if necessary */
@@ -789,8 +789,8 @@ SDL_RLEAlphaBlit(SDL_Surface * src, SDL_Rect * srcrect,
     }
 
     /* if left or right edge clipping needed, call clip blit */
-    if (srcrect->x || srcrect->w != src->w) {
-        RLEAlphaClipBlit(w, srcbuf, dst, dstbuf, srcrect);
+    if (srcrect->x || srcrect->w != surf_src->w) {
+        RLEAlphaClipBlit(w, srcbuf, surf_dst, dstbuf, srcrect);
     } else {
 
         /*
@@ -839,7 +839,7 @@ SDL_RLEAlphaBlit(SDL_Surface * src, SDL_Rect * srcrect,
             ofs += run;                  \
             }                            \
         } while(ofs < w);                    \
-        dstbuf += dst->pitch;                    \
+        dstbuf += surf_dst->pitch;                    \
         } while(--linecount);                    \
     } while(0)
 
@@ -859,8 +859,8 @@ SDL_RLEAlphaBlit(SDL_Surface * src, SDL_Rect * srcrect,
 
   done:
     /* Unlock the destination if necessary */
-    if (SDL_MUSTLOCK(dst)) {
-        SDL_UnlockSurface(dst);
+    if (SDL_MUSTLOCK(surf_dst)) {
+        SDL_UnlockSurface(surf_dst);
     }
     return 0;
 }
diff --git a/src/video/SDL_blit.h b/src/video/SDL_blit.h
index caf6c00f3..f12018d83 100644
--- a/src/video/SDL_blit.h
+++ b/src/video/SDL_blit.h
@@ -402,18 +402,18 @@ do {                                                                    \
 {                                                                       \
     switch (bpp) {                                                      \
         case 1: {                                                       \
-            Uint8 Pixel;                                                \
+            Uint8 _pixel;                                               \
                                                                         \
-            PIXEL_FROM_RGBA(Pixel, fmt, r, g, b, a);                    \
-            *((Uint8 *)(buf)) = Pixel;                                  \
+            PIXEL_FROM_RGBA(_pixel, fmt, r, g, b, a);                   \
+            *((Uint8 *)(buf)) = _pixel;                                 \
         }                                                               \
         break;                                                          \
                                                                         \
         case 2: {                                                       \
-            Uint16 Pixel;                                               \
+            Uint16 _pixel;                                              \
                                                                         \
-            PIXEL_FROM_RGBA(Pixel, fmt, r, g, b, a);                    \
-            *((Uint16 *)(buf)) = Pixel;                                 \
+            PIXEL_FROM_RGBA(_pixel, fmt, r, g, b, a);                   \
+            *((Uint16 *)(buf)) = _pixel;                                \
         }                                                               \
         break;                                                          \
                                                                         \
@@ -431,10 +431,10 @@ do {                                                                    \
         break;                                                          \
                                                                         \
         case 4: {                                                       \
-            Uint32 Pixel;                                               \
+            Uint32 _pixel;                                              \
                                                                         \
-            PIXEL_FROM_RGBA(Pixel, fmt, r, g, b, a);                    \
-            *((Uint32 *)(buf)) = Pixel;                                 \
+            PIXEL_FROM_RGBA(_pixel, fmt, r, g, b, a);                   \
+            *((Uint32 *)(buf)) = _pixel;                                \
         }                                                               \
         break;                                                          \
     }                                                                   \
diff --git a/src/video/SDL_video.c b/src/video/SDL_video.c
index dc6cf37b9..11492f608 100644
--- a/src/video/SDL_video.c
+++ b/src/video/SDL_video.c
@@ -232,16 +232,13 @@ ShouldUseTextureFramebuffer()
 }
 
 static int
-SDL_CreateWindowTexture(_THIS, SDL_Window * window, Uint32 * format, void ** pixels, int *pitch)
+SDL_CreateWindowTexture(SDL_VideoDevice *unused, SDL_Window * window, Uint32 * format, void ** pixels, int *pitch)
 {
     SDL_WindowTextureData *data;
-    SDL_RendererInfo info;
-    Uint32 i;
 
     data = SDL_GetWindowData(window, SDL_WINDOWTEXTUREDATA);
     if (!data) {
         SDL_Renderer *renderer = NULL;
-        SDL_RendererInfo info;
         int i;
         const char *hint = SDL_GetHint(SDL_HINT_FRAMEBUFFER_ACCELERATION);
 
@@ -249,6 +246,7 @@ SDL_CreateWindowTexture(_THIS, SDL_Window * window, Uint32 * format, void ** pix
         if (hint && *hint != '0' && *hint != '1' &&
             SDL_strcasecmp(hint, "software") != 0) {
             for (i = 0; i < SDL_GetNumRenderDrivers(); ++i) {
+                SDL_RendererInfo info;
                 SDL_GetRenderDriverInfo(i, &info);
                 if (SDL_strcasecmp(info.name, hint) == 0) {
                     renderer = SDL_CreateRenderer(window, i, 0);
@@ -259,6 +257,7 @@ SDL_CreateWindowTexture(_THIS, SDL_Window * window, Uint32 * format, void ** pix
         
         if (!renderer) {
             for (i = 0; i < SDL_GetNumRenderDrivers(); ++i) {
+                SDL_RendererInfo info;
                 SDL_GetRenderDriverInfo(i, &info);
                 if (SDL_strcmp(info.name, "software") != 0) {
                     renderer = SDL_CreateRenderer(window, i, 0);
@@ -291,17 +290,23 @@ SDL_CreateWindowTexture(_THIS, SDL_Window * window, Uint32 * format, void ** pix
     SDL_free(data->pixels);
     data->pixels = NULL;
 
-    if (SDL_GetRendererInfo(data->renderer, &info) < 0) {
-        return -1;
-    }
+    {
+        SDL_RendererInfo info;
+        Uint32 i;
 
-    /* Find the first format without an alpha channel */
-    *format = info.texture_formats[0];
-    for (i = 0; i < info.num_texture_formats; ++i) {
-        if (!SDL_ISPIXELFORMAT_FOURCC(info.texture_formats[i]) &&
-            !SDL_ISPIXELFORMAT_ALPHA(info.texture_formats[i])) {
-            *format = info.texture_formats[i];
-            break;
+        if (SDL_GetRendererInfo(data->renderer, &info) < 0) {
+            return -1;
+        }
+
+        /* Find the first format without an alpha channel */
+        *format = info.texture_formats[0];
+
+        for (i = 0; i < info.num_texture_formats; ++i) {
+            if (!SDL_ISPIXELFORMAT_FOURCC(info.texture_formats[i]) &&
+                    !SDL_ISPIXELFORMAT_ALPHA(info.texture_formats[i])) {
+                *format = info.texture_formats[i];
+                break;
+            }
         }
     }
 
@@ -330,7 +335,7 @@ SDL_CreateWindowTexture(_THIS, SDL_Window * window, Uint32 * format, void ** pix
 }
 
 static int
-SDL_UpdateWindowTexture(_THIS, SDL_Window * window, const SDL_Rect * rects, int numrects)
+SDL_UpdateWindowTexture(SDL_VideoDevice *unused, SDL_Window * window, const SDL_Rect * rects, int numrects)
 {
     SDL_WindowTextureData *data;
     SDL_Rect rect;
@@ -360,7 +365,7 @@ SDL_UpdateWindowTexture(_THIS, SDL_Window * window, const SDL_Rect * rects, int
 }
 
 static void
-SDL_DestroyWindowTexture(_THIS, SDL_Window * window)
+SDL_DestroyWindowTexture(SDL_VideoDevice *unused, SDL_Window * window)
 {
     SDL_WindowTextureData *data;
 
diff --git a/src/video/x11/SDL_x11modes.c b/src/video/x11/SDL_x11modes.c
index 6336f0cab..cd7b38c50 100644
--- a/src/video/x11/SDL_x11modes.c
+++ b/src/video/x11/SDL_x11modes.c
@@ -674,7 +674,6 @@ X11_GetDisplayModes(_THIS, SDL_VideoDisplay * sdl_display)
     int screen_w;
     int screen_h;
     SDL_DisplayMode mode;
-    SDL_DisplayModeData *modedata;
 
     /* Unfortunately X11 requires the window to be created with the correct
      * visual and depth ahead of time, but the SDL API allows you to create
@@ -692,6 +691,7 @@ X11_GetDisplayModes(_THIS, SDL_VideoDisplay * sdl_display)
     if (data->use_xinerama) {
         if (data->use_vidmode && !data->xinerama_info.x_org && !data->xinerama_info.y_org &&
            (screen_w > data->xinerama_info.width || screen_h > data->xinerama_info.height)) {
+            SDL_DisplayModeData *modedata;
             /* Add the full (both screens combined) xinerama mode only on the display that starts at 0,0
              * if we're using vidmode.
              */
@@ -707,6 +707,7 @@ X11_GetDisplayModes(_THIS, SDL_VideoDisplay * sdl_display)
         }
         else if (!data->use_xrandr)
         {
+            SDL_DisplayModeData *modedata;
             /* Add the current mode of each monitor otherwise if we can't get them from xrandr */
             mode.w = data->xinerama_info.width;
             mode.h = data->xinerama_info.height;
@@ -759,6 +760,7 @@ X11_GetDisplayModes(_THIS, SDL_VideoDisplay * sdl_display)
     if (data->use_vidmode &&
         X11_XF86VidModeGetAllModeLines(display, data->vidmode_screen, &nmodes, &modes)) {
         int i;
+        SDL_DisplayModeData *modedata;
 
 #ifdef X11MODES_DEBUG
         printf("VidMode modes: (unsorted)\n");
@@ -787,6 +789,7 @@ X11_GetDisplayModes(_THIS, SDL_VideoDisplay * sdl_display)
 #endif /* SDL_VIDEO_DRIVER_X11_XVIDMODE */
 
     if (!data->use_xrandr && !data->use_vidmode) {
+        SDL_DisplayModeData *modedata;
         /* Add the desktop mode */
         mode = sdl_display->desktop_mode;
         modedata = (SDL_DisplayModeData *) SDL_calloc(1, sizeof(SDL_DisplayModeData));
diff --git a/src/video/x11/edid-parse.c b/src/video/x11/edid-parse.c
index 8608bf254..2c145e23c 100644
--- a/src/video/x11/edid-parse.c
+++ b/src/video/x11/edid-parse.c
@@ -548,7 +548,6 @@ yesno (int v)
 void
 dump_monitor_info (MonitorInfo *info)
 {
-    char *s;
     int i;
     
     printf ("Checksum: %d (%s)\n",
@@ -601,6 +600,7 @@ dump_monitor_info (MonitorInfo *info)
     }
     else
     {
+       const char *s;
 	printf ("Video Signal Level: %f\n", info->analog.video_signal_level);
 	printf ("Sync Signal Level: %f\n", info->analog.sync_signal_level);
 	printf ("Total Signal Level: %f\n", info->analog.total_signal_level);