Don't explicitly link to libraries (use libdl instead)

[jljusten]

For platforms that support libdl, we should not link directly to libraries.

Instead, libwaffle should dlopen libraries at runtime.

This will allow libwaffle to be used in scenarios where the other system libraries are not installed.

For example, this should be possible:

• Build libwaffle with glx and wayland support
• Run a waffle application on wayland even if glx libraries are not installed on the system

[evelikov]

Rough split of current dependencies:

• [x] libEGL
• [x] libGL
• [x] libgbm
• [ ] libudev
• [ ] libwayland*
• [ ] lib{X11,xcb}*

[evelikov]

libEGL - v1, v2 Tested

• [x] x11_egl - evelikov, jljusten
• [x] gbm - jljusten
• [x] wayland - pq
• [ ] Android

Todo:

• Use libEGL.so.1 for Linux (fixed with v2)
• Fix the Android build (fixed with v2)

[evelikov]

The libX11* dependencies

• libX11 - XFree, XOpenDisplay, XCloseDisplay, XSetErrorHandler
• libX11-xcb - XGetXCBConnection

The above could be replaced with

• XFree - free (?)
• XOpenDisplay, XSetErrorHandler, XGetXCBConnection - xcb_connect + xcb_connection_has_error
• XCloseDisplay - xcb_disconnect

Update: the above has to be done once piglit is "fixed" to use xcb alone - currently it uses a strange mix of xlib + xcb.

[evelikov]

libgbm, libGL v1

Tested:

• [x] glx - evelikov
• [x] x11_egl - evelikov
• [x] gbm - evelikov (note it actually fails, due to a mesa bug)

[evelikov]

libwayland* v1, Patch 4 v2

Tested:

• [x] wayland - evelikov (v2)