build: libweston doesn't need -export-dynamic

According to https://gitlab.freedesktop.org/wayland/weston/merge_requests/159#note_148104
it doesn't make sense to use export-dynamic on libraries.

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
Reported-by: Pekka Paalanen <pekka.paalanen@collabora.com>

libweston/meson.build

@@ -68,7 +68,6 @@ lib_weston = shared_library(
 	'weston-@0@'.format(libweston_major),
 	srcs_libweston,
 	include_directories: [ include_directories('..', '../shared'), public_inc ],
-	link_args: [ '-Wl,-export-dynamic' ],
 	install: true,
 	version: '0.0.@0@'.format(libweston_revision),
 	link_whole: lib_libshared,