egl: Add EGL_DRIVERS_PATH environment variable.
EGL_DRIVERS_PATH gives a list of colon-separated directories. The given
directories will be searched when preloading drivers.
This is based on Mike Stroyan's patch, which honors the variable in
_eglPreloadDisplayDrivers. It is extended to honor the variable also in
_eglPreloadUserDriver and _eglPreloadDefaultDriver in this version.
diff --git a/docs/egl.html b/docs/egl.html
index 87f7e7d..8a2ea7c 100644
--- a/docs/egl.html
+++ b/docs/egl.html
@@ -126,6 +126,15 @@
runtime</p>
<ul>
+<li><code>EGL_DRIVERS_PATH</code>
+
+<p>By default, the main library will look for drivers in the directory where
+the drivers are installed to. This variable specifies a list of
+colon-separated directories where the main library will look for drivers, in
+addition to the default directory.</p>
+
+</li>
+
<li><code>EGL_DRIVER</code>
<p>This variable specifies a full path to an EGL driver and it forces the