Library is missing the link with GLEW and freetype libraries

glew* symbols are missing:
```
$ LD_PRELOAD=/usr/local/lib/libfreetype-gl.so ls
ld-elf.so.1: /usr/local/lib/libfreetype-gl.so: Undefined symbol "__glewEnableVertexAttribArray"
```

freetype symbols are also missing:
```
ld: error: /usr/local/lib/libfreetype-gl.so: undefined reference to FT_Glyph_StrokeBorder
```


It needs the link flags ```-lGLEW -lfreetype```.
