Prevent a crash in Windows AMD drivers

Usually, when window is being created without SDL_WINDOW_OPENGL flag,
SDL2 internally re-creates it to support OpenGL during
SDL_CreateRenderer if needed.

This leads to crash in AMD OpenGL drivers (Windows only), which happens
for drivers: "opengl", "opengles", "opengles2".

When the window is created with correct flag from the get-go, the crash
does not happen.

On Linux, the code does not crash either way (at least not when using
Mesa and AMDGPU open source driver), so there's no point in propagating
the hack.

Also, remove a comment that is no longer relevant to the code below.

include/support.h

@@ -122,4 +122,9 @@ void upcase(std::string &str);
 void lowcase(std::string &str);
 void strip_punctuation(std::string &str);
 
+template<size_t N>
+bool starts_with(const char (& pfx)[N], const std::string &str) noexcept {
+	return (strncmp(pfx, str.c_str(), N) == 0);
+}
+
 #endif