Ensure builds without --fpermissive flag

[bkmgit]

May close #15

[onecoolx]

Thank you so much

[onecoolx]

But some checks are not passed on ubuntu linux, can you check it? @bkmgit

[bkmgit]

Issue is that it is using system library includes. Bundled Freetype 2.3.6 has char* for tags in FT_Outline
https://github.com/onecoolx/picasso/blob/master/third_party/freetype-2.3.6/include/freetype/ftimage.h#L338-L349

Freetype 2.13.3 or later has unsigned char*
https://freetype.org/freetype2/docs/reference/ft2-outline_processing.html
https://github.com/freetype/freetype/blob/master/docs/CHANGES#L19-L26
https://github.com/freetype/freetype/blob/master/include/freetype/ftimage.h#L351-L362

[onecoolx]

Issue is that it is using system library includes. Bundled Freetype 2.3.6 has char* for tags in FT_Outline https://github.com/onecoolx/picasso/blob/master/third_party/freetype-2.3.6/include/freetype/ftimage.h#L338-L349

Freetype 2.13.3 or later has unsigned char* https://freetype.org/freetype2/docs/reference/ft2-outline_processing.html https://github.com/freetype/freetype/blob/master/docs/CHANGES#L19-L26 https://github.com/freetype/freetype/blob/master/include/freetype/ftimage.h#L351-L362

I modified it and used forced conversion.

[bkmgit]

Thanks.