Merge pull request #2753 from basilfx/feature/signed_compare

fix: several compilation issues under LLVM and more

csrc/u8g2_arc.c

@@ -75,7 +75,7 @@ static void u8g2_draw_arc(u8g2_t *u8g2, u8g2_uint_t x0, u8g2_uint_t y0, u8g2_uin
       d = d - 2 * x - 1;
       x = x + 1;
     }
-    else if (d < 2 * (rad - y))
+    else if (d < 2 * ((u8g2_int_t)rad - y))
     {
       d = d + 2 * y - 1;
       y = y - 1;

csrc/u8g2_ll_hvline.c

@@ -77,6 +77,7 @@ void u8g2_ll_hvline_vertical_top_lsb(u8g2_t *u8g2, u8g2_uint_t x, u8g2_uint_t y,
   uint8_t or_mask, xor_mask;
 #ifdef __unix
   uint8_t *max_ptr = u8g2->tile_buf_ptr + u8g2_GetU8x8(u8g2)->display_info->tile_width*u8g2->tile_buf_height*8;
+  (void)max_ptr;	/* silence unused variable warning if asserts are disabled */
 #endif
 
   //assert(x >= u8g2->buf_x0);

sys/sdl/common/u8x8_d_sdl_128x64.c

@@ -8,6 +8,7 @@
 #endif
 #include <assert.h>
 #include <stdio.h>
+#include <string.h>
 
 //#define HEIGHT (64)
 //#define WIDTH 128
@@ -36,7 +37,7 @@ int u8g_sdl_height, u8g_sdl_width;
 
 static void u8g_sdl_set_pixel(int x, int y, int idx)
 {
-  uint32_t  *ptr;
+  uint8_t  *ptr;
   uint32_t offset;
   int i, j;
   
@@ -59,8 +60,8 @@ static void u8g_sdl_set_pixel(int x, int y, int idx)
         
       assert( offset < (Uint32)(u8g_sdl_width * u8g_sdl_multiple * u8g_sdl_height * u8g_sdl_multiple * u8g_sdl_screen->format->BytesPerPixel) );
       
-      ptr = (uint32_t *)(((uint8_t *)(u8g_sdl_screen->pixels)) + offset);
-      *ptr = u8g_sdl_color[idx];
+      ptr = ((uint8_t *)(u8g_sdl_screen->pixels)) + offset;
+      memcpy(ptr, &u8g_sdl_color[idx], sizeof(u8g_sdl_color[idx]));
 #endif
     }
 }