scons: Updates for targets/egl-static.

Update SConscripts to re-enable or add support for EGL on windows and
x11 platforms respectively.  targets/egl-gdi is replaced by
targets/egl-static, where "-static" means pipe drivers and state
trackers are linked to statically by egl_gallium, and egl_gallium is a
built-in driver of libEGL.  There is no more egl_gallium.dll on Windows.

src/mapi/vgapi/SConscript

@@ -51,6 +51,9 @@ if env['platform'] != 'winddk':
 
 	env.InstallSharedLibrary(openvg, version=(1, 0, 0))
 
-	vgapi = [env.FindIxes(openvg, 'LIBPREFIX', 'LIBSUFFIX')]
+	if env['platform'] == 'windows':
+	    vgapi = env.FindIxes(openvg, 'LIBPREFIX', 'LIBSUFFIX')
+	else:
+	    vgapi = env.FindIxes(openvg, 'SHLIBPREFIX', 'SHLIBSUFFIX')
 
 	Export(['vgapi'])