Update header comments about how the implementation works.

include/epoxy/egl.h

@@ -23,13 +23,8 @@
 
 /** @file egl.h
  *
- * Provides an implementation of a EGL dispatch layer using a hidden
+ * Provides an implementation of an EGL dispatch layer using global
- * vtable.
+ * function pointers
- *
- * This is a lower performance path than ifuncs when they are
- * available, but it is required if you might have multiple return
- * values for GetProcAddress/dlsym()ed functions (for example, if you
- * unload libGL.so.1).
  */
 
 #ifndef __EPOXY_EGL_H

include/epoxy/gl.h

@@ -23,15 +23,8 @@
 
 /** @file gl.h
  *
- * Provides an implementation of a GL dispatch layer using a hidden
+ * Provides an implementation of a GL dispatch layer using either
- * vtable.
+ * global function pointers or a hidden vtable.
- *
- * This is a lower performance path than ifuncs when they are
- * available, but it is required if you might have multiple return
- * values for GetProcAddress/dlsym()ed functions.  That is the case if
- * you're using WGL (which can return different function pointers per
- * context), or if you dlclose() and re-dlopen() libGL (which means
- * you'll get different dynamically allocated dispatch stubs).
  */
 
 #ifndef __EPOXY_GL_H

include/epoxy/glx.h

@@ -23,13 +23,8 @@
 
 /** @file glx.h
  *
- * Provides an implementation of a GLX dispatch layer using a hidden
+ * Provides an implementation of a GLX dispatch layer using global
- * vtable.
+ * function pointers.
- *
- * This is a lower performance path than ifuncs when they are
- * available, but it is required if you might have multiple return
- * values for GetProcAddress/dlsym()ed functions (for example, if you
- * unload libGL.so.1).
  */
 
 #ifndef __EPOXY_GLX_H