Fixed minor warning. Added comment.

backends/imgui_impl_opengl3.cpp

@@ -303,6 +303,7 @@ bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
     // GLES 2
     bd->GlVersion = 200;
     bd->GlProfileIsES2 = true;
+    IM_UNUSED(gl_version_str);
 #else
     // Desktop or GLES 3
     GLint major = 0;

imgui.cpp

@@ -2399,7 +2399,7 @@ int ImTextCharFromUtf8(unsigned int* out_char, const char* in_text, const char*
     int e = 0;
     e  = (*out_char < mins[len]) << 6; // non-canonical encoding
     e |= ((*out_char >> 11) == 0x1b) << 7;  // surrogate half?
-    e |= (*out_char > IM_UNICODE_CODEPOINT_MAX) << 8;  // out of range?
+    e |= (*out_char > IM_UNICODE_CODEPOINT_MAX) << 8;  // out of range we can store in ImWchar (FIXME: May evolve)
     e |= (s[1] & 0xc0) >> 2;
     e |= (s[2] & 0xc0) >> 4;
     e |= (s[3]       ) >> 6;