Link against runtime on OSX and Windows because they seem to insist on all symbols being present.

test cases/common/125 shared module/meson.build

@@ -2,7 +2,18 @@ project('shared module', 'c')
 
 dl = meson.get_compiler('c').find_library('dl', required : false)
 l = shared_library('runtime', 'runtime.c')
-m = shared_module('mymodule', 'module.c')
+if host_machine.system() == 'darwin' or host_machine.system() == 'windows'
+  # At least in OSX and seemingly also on Windows you must have
+  # all symbols present when linking a module.
+  #
+  # In Linux many projects build plugins without linking to
+  # the runtime so they have undefined symbols. We need to support
+  # both for ease of transitioning.
+  mlink = [l]
+else
+  mlink = []
+endif
+m = shared_module('mymodule', 'module.c', link_with : mlink)
 e = executable('prog', 'prog.c', link_with : l, dependencies : dl)
 test('import test', e, args : [m.full_path()])
 

test cases/common/125 shared module/runtime.c

@@ -14,6 +14,6 @@
  * modules.
  */
 
-int func_from_language_runtime() {
+int DLL_PUBLIC func_from_language_runtime() {
     return 86;
 }