Fixed IMGUI_API tag on ImFontAtlas::IsBuilt() preventing to build as DLL on some setups. (#2226)

imgui.h

@@ -1903,9 +1903,9 @@ struct ImFontAtlas
     // Building in RGBA32 format is provided for convenience and compatibility, but note that unless you manually manipulate or copy color data into 
     // the texture (e.g. when using the AddCustomRect*** api), then the RGB pixels emitted will always be white (~75% of memory/bandwidth waste.
     IMGUI_API bool              Build();                    // Build pixels data. This is called automatically for you by the GetTexData*** functions.
-    IMGUI_API bool              IsBuilt()                   { return Fonts.Size > 0 && (TexPixelsAlpha8 != NULL || TexPixelsRGBA32 != NULL); }
     IMGUI_API void              GetTexDataAsAlpha8(unsigned char** out_pixels, int* out_width, int* out_height, int* out_bytes_per_pixel = NULL);  // 1 byte per-pixel
     IMGUI_API void              GetTexDataAsRGBA32(unsigned char** out_pixels, int* out_width, int* out_height, int* out_bytes_per_pixel = NULL);  // 4 bytes-per-pixel
+    bool                        IsBuilt()                   { return Fonts.Size > 0 && (TexPixelsAlpha8 != NULL || TexPixelsRGBA32 != NULL); }
     void                        SetTexID(ImTextureID id)    { TexID = id; }
 
     //-------------------------------------------