imgui_freetype: fix warnings (#6104), fix typos. (#6079)

misc/freetype/README.md

@@ -24,7 +24,7 @@ See https://gist.github.com/ocornut/b3a9ecf13502fd818799a452969649ad
 
 - Oversampling settins are ignored but also not so much necessary with the higher quality rendering.
 
-### Comparaison
+### Comparison
 
 Small, thin anti-aliased fonts typically benefit a lot from FreeType's hinting:
 ![comparing_font_rasterizers](https://user-images.githubusercontent.com/8225057/107550178-fef87f00-6bd0-11eb-8d09-e2edb2f0ccfc.gif)

misc/freetype/imgui_freetype.cpp

@@ -43,13 +43,16 @@
 #include FT_SYNTHESIS_H         // <freetype/ftsynth.h>
 
 #ifdef _MSC_VER
+#pragma warning (push)
 #pragma warning (disable: 4505)     // unreferenced local function has been removed (stb stuff)
 #pragma warning (disable: 26812)    // [Static Analyzer] The enum type 'xxx' is unscoped. Prefer 'enum class' over 'enum' (Enum.3).
 #endif
 
-#if defined(__GNUC__)
+#ifdef __GNUC__
+#pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wpragmas"                  // warning: unknown option after '#pragma GCC diagnostic' kind
 #pragma GCC diagnostic ignored "-Wunused-function"          // warning: 'xxxx' defined but not used
+#pragma GCC diagnostic ignored "-Wsubobject-linkage"        // warning: 'xxxx' has a field ‘xxxx’ whose type uses the anonymous namespace
 #endif
 
 //-------------------------------------------------------------------------
@@ -348,7 +351,7 @@ namespace
             IM_ASSERT(0 && "FreeTypeFont::BlitGlyph(): Unknown bitmap pixel mode!");
         }
     }
-}
+} // namespace
 
 #ifndef STB_RECT_PACK_IMPLEMENTATION                        // in case the user already have an implementation in the _same_ compilation unit (e.g. unity builds)
 #ifndef IMGUI_DISABLE_STB_RECT_PACK_IMPLEMENTATION
@@ -779,3 +782,11 @@ void ImGuiFreeType::SetAllocatorFunctions(void* (*alloc_func)(size_t sz, void* u
     GImGuiFreeTypeFreeFunc = free_func;
     GImGuiFreeTypeAllocatorUserData = user_data;
 }
+
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
+
+#ifdef _MSC_VER
+#pragma warning (pop)
+#endif