meson: sort C warning flags alphabetically

When scanning the list of warning flags to see if one is present, it is
helpful if they are in alphabetical order. It is further helpful to
separate out the 'no-' prefixed warnings.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

meson.build

@@ -571,36 +571,38 @@ qemu_common_flags += cc.get_supported_arguments(hardening_flags)
 add_global_arguments(qemu_common_flags, native: false, language: all_languages)
 add_global_link_arguments(qemu_ldflags, native: false, language: all_languages)
 
-# Collect warnings that we want to enable
-
+# Collect warning flags we want to set, sorted alphabetically
 warn_flags = [
-  '-Wundef',
-  '-Wwrite-strings',
-  '-Wmissing-prototypes',
-  '-Wstrict-prototypes',
-  '-Wredundant-decls',
-  '-Wold-style-declaration',
-  '-Wold-style-definition',
-  '-Wtype-limits',
-  '-Wformat-security',
-  '-Wformat-y2k',
-  '-Winit-self',
-  '-Wignored-qualifiers',
+  # First enable interesting warnings
   '-Wempty-body',
-  '-Wnested-externs',
   '-Wendif-labels',
   '-Wexpansion-to-defined',
+  '-Wformat-security',
+  '-Wformat-y2k',
+  '-Wignored-qualifiers',
   '-Wimplicit-fallthrough=2',
+  '-Winit-self',
   '-Wmissing-format-attribute',
+  '-Wmissing-prototypes',
+  '-Wnested-externs',
+  '-Wold-style-declaration',
+  '-Wold-style-definition',
+  '-Wredundant-decls',
+  '-Wshadow=local',
+  '-Wstrict-prototypes',
+  '-Wtype-limits',
+  '-Wundef',
+  '-Wwrite-strings',
+
+  # Then disable some undesirable warnings
+  '-Wno-gnu-variable-sized-type-not-at-end',
   '-Wno-initializer-overrides',
   '-Wno-missing-include-dirs',
+  '-Wno-psabi',
   '-Wno-shift-negative-value',
   '-Wno-string-plus-int',
-  '-Wno-typedef-redefinition',
   '-Wno-tautological-type-limit-compare',
-  '-Wno-psabi',
-  '-Wno-gnu-variable-sized-type-not-at-end',
-  '-Wshadow=local',
+  '-Wno-typedef-redefinition',
 ]
 
 if host_os != 'darwin'