Fix hidden symbol test for Windows clang

This only happened to work with MSVC by accident (since shared libraries
don't export symbols by default with that)

test cases/failing build/2 hidden symbol/meson.build

@@ -1,10 +1,7 @@
 project('hidden symbol', 'c')
 
 if host_machine.system() == 'windows' or host_machine.system() == 'cygwin'
-  cc = meson.get_compiler('c')
-  if cc.get_id() == 'gcc'
-    error('MESON_SKIP_TEST -fvisibility=hidden does not work on MinGW or Cygwin.')
-  endif
+  error('MESON_SKIP_TEST -fvisibility=hidden does not work for PE files.')
 endif
 
 l = shared_library('bob', 'bob.c',