Carve out everything but gstreamer plugin part, libnice-0.1.21

Signed-off-by: Igor V. Kovalenko <igor.v.kovalenko@gmail.com>

diff -udBbr libnice-0.1.21-original/meson.build libnice-0.1.21/meson.build
--- libnice-0.1.21-original/meson.build	2020-10-21 04:03:07.272845300 +0300
+++ libnice-0.1.21/meson.build	2022-03-20 23:38:05.116302874 +0300
@@ -263,9 +263,7 @@
 
 libm = cc.find_library('m', required: false)
 
-nice_incs = include_directories('.', 'agent', 'random', 'socket', 'stun')
-
-nice_deps = gio_deps + [gthread_dep, crypto_dep, gupnp_igd_dep] + syslibs
+nice_incs = include_directories('.')

 ignored_iface_prefix = get_option('ignored-network-interface-prefix')
 if ignored_iface_prefix != []
@@ -278,11 +276,7 @@
 
 gir = find_program('g-ir-scanner', required : get_option('introspection'))
 
-subdir('agent')
-subdir('stun')
-subdir('socket')
-subdir('random')
-subdir('nice')
+libnice_dep = dependency('nice', version: nice_version, required: true)
 
 if gst_dep.found()
   subdir('gst')
@@ -298,14 +292,6 @@
   endif
 endif
 
-if not get_option('tests').disabled()
-  subdir('tests')
-endif
-
-if not get_option('examples').disabled()
-  subdir('examples')
-endif
-
 add_test_setup('valgrind',
 	       exe_wrapper: ['valgrind',
 			     '--leak-check=full',