meson: use -fno-strict-aliasing where supported

https://bugzilla.gnome.org/show_bug.cgi?id=769183

ext/sidplay/meson.build

@@ -1,11 +1,13 @@
 # sidplay plugin works with libsidplay 1.36.x (not 2.x.x)
 have_sidplay = false
 if add_languages('cpp')
+  extra_args = []
   cxx = meson.get_compiler('cpp')
   if cxx.has_argument('-fvisibility=hidden')
-    cxx_vis_args = ['-fvisibility=hidden']
-  else
-    cxx_vis_args = []
+    extra_args += ['-fvisibility=hidden']
+  endif
+  if cxx.has_argument('-fno-strict-aliasing')
+    extra_args += ['-fno-strict-aliasing']
   endif
 
   if cxx.has_header('sidplay/player.h')
@@ -22,7 +24,7 @@ endif
 
 if have_sidplay
   shared_module('gstsid', 'gstsiddec.cc',
-    cpp_args : ugly_args + cxx_vis_args,
+    cpp_args : ugly_args + extra_args,
     include_directories : [configinc],
     dependencies : [gstaudio_dep, sidplay_dep],
     install : true,

meson.build

@@ -47,6 +47,11 @@ if cc.has_argument('-fvisibility=hidden')
   add_project_arguments('-fvisibility=hidden', language: 'c')
 endif
 
+# Disable strict aliasing
+if cc.has_argument('-fno-strict-aliasing')
+  add_project_arguments('-fno-strict-aliasing', language: 'c')
+endif
+
 cdata = configuration_data()
 check_headers = [
   ['HAVE_DLFCN_H', 'dlfcn.h'],