Fix imgui compile and link error for wasm (#2297)

Author: halx99

extensions/ImGui/CMakeLists.txt

@@ -74,6 +74,10 @@ add_library(${target_name} STATIC
         ${HEADER}
         ${SOURCE})
 
+if(WASM)
+    target_compile_definitions(${target_name} PRIVATE EMSCRIPTEN_USE_EMBEDDED_GLFW3=1)
+endif()
+
 target_include_directories(${target_name} 
     PUBLIC src
     PUBLIC src/ImGui/imgui

extensions/ImGui/src/ImGui/imgui/imgui.h

@@ -3573,9 +3573,9 @@ struct ImFont
     // Methods
     IMGUI_API ImFont();
     IMGUI_API ~ImFont();
-    IMGUI_API const ImFontGlyph*FindGlyph(ImWchar c);
-    IMGUI_API const ImFontGlyph*FindGlyphNoFallback(ImWchar c);
-    float                       GetCharAdvance(ImWchar c)           { return ((int)c < IndexAdvanceX.Size) ? IndexAdvanceX[(int)c] : FallbackAdvanceX; }
+    IMGUI_API const ImFontGlyph*FindGlyph(ImWchar c) const;
+    IMGUI_API const ImFontGlyph*FindGlyphNoFallback(ImWchar c) const;
+    float                       GetCharAdvance(ImWchar c) const     { return ((int)c < IndexAdvanceX.Size) ? IndexAdvanceX[(int)c] : FallbackAdvanceX; }
     bool                        IsLoaded() const                    { return ContainerAtlas != NULL; }
     const char*                 GetDebugName() const                { return ConfigData ? ConfigData->Name : "<unknown>"; }
 
@@ -3593,7 +3593,7 @@ struct ImFont
     IMGUI_API void              AddGlyph(const ImFontConfig* src_cfg, ImWchar c, float x0, float y0, float x1, float y1, float u0, float v0, float u1, float v1, float advance_x);
     IMGUI_API void              AddRemapChar(ImWchar dst, ImWchar src, bool overwrite_dst = true); // Makes 'dst' character/glyph points to 'src' character/glyph. Currently needs to be called AFTER fonts have been built.
     IMGUI_API void              SetGlyphVisible(ImWchar c, bool visible);
-    IMGUI_API bool              IsGlyphRangeUnused(unsigned int c_begin, unsigned int c_last);
+    IMGUI_API bool              IsGlyphRangeUnused(unsigned int c_begin, unsigned int c_last) const;
 };
 
 //-----------------------------------------------------------------------------

extensions/ImGui/src/ImGui/imgui/imgui_draw.cpp

@@ -3770,7 +3770,7 @@ void ImFont::BuildLookupTable()
 
 // API is designed this way to avoid exposing the 4K page size
 // e.g. use with IsGlyphRangeUnused(0, 255)
-bool ImFont::IsGlyphRangeUnused(unsigned int c_begin, unsigned int c_last)
+bool ImFont::IsGlyphRangeUnused(unsigned int c_begin, unsigned int c_last) const
 {
     unsigned int page_begin = (c_begin / 4096);
     unsigned int page_last = (c_last / 4096);
@@ -3860,7 +3860,7 @@ void ImFont::AddRemapChar(ImWchar dst, ImWchar src, bool overwrite_dst)
 }
 
 // Find glyph, return fallback if missing
-const ImFontGlyph* ImFont::FindGlyph(ImWchar c)
+const ImFontGlyph* ImFont::FindGlyph(ImWchar c) const
 {
     if (c >= (size_t)IndexLookup.Size)
         return FallbackGlyph;
@@ -3870,7 +3870,7 @@ const ImFontGlyph* ImFont::FindGlyph(ImWchar c)
     return &Glyphs.Data[i];
 }
 
-const ImFontGlyph* ImFont::FindGlyphNoFallback(ImWchar c)
+const ImFontGlyph* ImFont::FindGlyphNoFallback(ImWchar c) const
 {
     if (c >= (size_t)IndexLookup.Size)
         return NULL;