meson.build: Order warning flags alphabetically

... and remove the duplicate we already had.

meson.build

@@ -227,41 +227,40 @@ if cc.get_id() == 'msvc'
 elif cc.get_id() == 'gcc' or cc.get_id() == 'clang'
   test_cflags = [
     '-fno-strict-aliasing',
-    '-Wpointer-arith',
-    '-Wmissing-declarations',
-    '-Wimplicit-function-declaration',
+    '-Wcast-align',
     '-Wformat=2',
     '-Wformat-nonliteral',
     '-Wformat-security',
-    '-Wstrict-prototypes',
+    '-Wignored-qualifiers',
+    '-Wimplicit-function-declaration',
+    '-Wlogical-op',
+    '-Wmissing-format-attribute',
+    '-Wmissing-include-dirs',
+    '-Wmissing-noreturn',
+    '-Wmissing-declarations',
     '-Wmissing-prototypes',
     '-Wnested-externs',
     '-Wold-style-definition',
-    '-Wundef',
-    '-Wunused',
-    '-Wcast-align',
-    '-Wmissing-noreturn',
-    '-Wmissing-format-attribute',
-    '-Wmissing-include-dirs',
-    '-Wlogical-op',
+    '-Wpointer-arith',
+    '-Wstrict-prototypes',
     '-Wswitch-default',
     '-Wswitch-enum',
-    '-Wignored-qualifiers',
-    '-Werror=redundant-decls',
+    '-Wundef',
+    '-Wunused',
+    '-Werror=address',
+    '-Werror=array-bounds',
+    '-Werror=empty-body',
     '-Werror=implicit',
-    '-Werror=nonnull',
     '-Werror=init-self',
+    '-Werror=int-to-pointer-cast',
     '-Werror=main',
     '-Werror=missing-braces',
-    '-Werror=sequence-point',
-    '-Werror=return-type',
-    '-Werror=trigraphs',
-    '-Werror=array-bounds',
-    '-Werror=write-strings',
-    '-Werror=address',
-    '-Werror=int-to-pointer-cast',
+    '-Werror=nonnull',
     '-Werror=pointer-to-int-cast',
-    '-Werror=empty-body',
+    '-Werror=redundant-decls',
+    '-Werror=return-type',
+    '-Werror=sequence-point',
+    '-Werror=trigraphs',
     '-Werror=write-strings',
   ]
 else