wflinfo: use waffle_dl_sym to get glGetStringi
Created by: fjhenigman
Wflinfo tries to use glGetStringi when the gl version >= 3.0, but eglGetProcAddress cannot be relied on to get core functions like glGetStringi unless the egl version is 1.5 or higher. Dlsym works with lower egl versions. This lets wflinfo work on platforms where egl < 1.5 and gl >= 3.0, e.g. mali.