Resolve "Compile SDL2_ttf for buildroot/Recalbox"

Please make sure your MR is ready to be merged !

• You added the changes in CHANGELOG.md
• You described the MR as below
• You updated the recalbox wiki
• You wrote a blog post on recalbox-blog

Changes : Add a patch for SDL2_ttf, based on Mercurial revision https://hg.libsdl.org/SDL_ttf/rev/3b93536d291a.

Improve the detection of OpenGL library in "configure" command.

So, the usage of this library is disabled and SDL2_ttf compiles without problem.

Closes #448 (closed)