Make the default font loadable before InitWindow, for use with the image API.

Make the default font loader early out if we have already loaded parts of it, so we don't leak memory

src/rtext.c

@@ -161,6 +161,10 @@ extern void LoadFontDefault(void)
 {
     #define BIT_CHECK(a,b) ((a) & (1u << (b)))
 
+    // check to see if we have allready allocated the font for an image, and if we don't need to upload, then just return
+    if (defaultFont.glyphs != NULL && !isGpuReady) 
+        return;
+
     // NOTE: Using UTF-8 encoding table for Unicode U+0000..U+00FF Basic Latin + Latin-1 Supplement
     // Ref: http://www.utf8-chartable.de/unicode-utf8-table.pl
 
@@ -256,8 +260,19 @@ extern void LoadFontDefault(void)
 
         counter++;
     }
-
-    if (isGpuReady) defaultFont.texture = LoadTextureFromImage(imFont);
+    
+    if (isGpuReady)
+    {
+        defaultFont.texture = LoadTextureFromImage(imFont);
+        
+        // we have already loaded the font glyph data an image, and the GPU is ready, we are done
+        // if we don't do this, we will leak memory by reallocating the glyphs and rects
+        if (defaultFont.glyphs != NULL)
+        {
+            UnloadImage(imFont);
+            return;
+        }
+    }
 
     // Reconstruct charSet using charsWidth[], charsHeight, charsDivisor, glyphCount
     //------------------------------------------------------------------------------
@@ -282,7 +297,7 @@ extern void LoadFontDefault(void)
 
         testPosX += (int)(defaultFont.recs[i].width + (float)charsDivisor);
 
-        if (testPosX >= defaultFont.texture.width)
+        if (testPosX >= imFont.width)
         {
             currentLine++;
             currentPosX = 2*charsDivisor + charsWidth[i];