[meson] better propagate dependencies

The emper header LockedUnboundedQueue.hpp could depend on different libraries
according to the implementation.

To link those dependencies with everything including LockedUnboundedQueue.hpp
we propagate all emper_dependencies through emper_dep.

And using emper_dep as a dependency seems anyway better than essentially
writing down emper_dep manually each time.

emper_dep essentially is:
(link_with:emper, include_directories: emper_all_include)

emper/meson.build

@@ -54,7 +54,8 @@ emper = library(
 
 emper_dep = declare_dependency(
   include_directories : emper_all_include,
-  link_with : emper
+  link_with : emper,
+  dependencies : emper_dependencies,
 )
 
 
@@ -65,8 +66,7 @@ emper_c_sources = [
 emper_c = library(
   'emper-c',
   emper_c_sources,
-  include_directories: emper_all_include,
-  link_with: emper,
+  dependencies: emper_dep,
   install: true,
 )
 

eval/meson.build

 executable(
   'time_to_spawn',
   'TimeToSpawn.cpp',
-  include_directories: emper_all_include,
-  dependencies: thread_dep,
-  link_with: emper,
+  dependencies: emper_dep,
 )
 
 executable(
   'spawn_a_lot',
   'SpawnALot.cpp',
-  include_directories: emper_all_include,
-  dependencies: thread_dep,
-  link_with: emper,
+  dependencies: emper_dep,
 )
 
 executable(
   'locality',
   'Locality.cpp',
-  include_directories: emper_all_include,
-  link_with: emper,
+  dependencies: emper_dep,
 )

tests/fixtures/meson.build

@@ -5,8 +5,7 @@ test_fixtures_sources = ['network.cpp']
 test_fixtures_lib = library(
 	'test-fixtures',
 	test_fixtures_sources,
-	include_directories: emper_all_include,
-	link_with: emper,
+	dependencies: emper_dep,
 )
 
 test_fixtures = declare_dependency(