meson: remove unneeded windows defines

They are used to enable _USE_MATH_DEFINES or __USE_MINGW_ANSI_STDIO, which we
already define.

config.h.meson

@@ -18,9 +18,6 @@
 /* Define if the zvbi module is built */
 // #undef ZVBI_COMPILED
 
-/* ISO C, POSIX, and 4.3BSD things. */
-#mesondefine _BSD_SOURCE
-
 /* Define to 64 for large files support. */
 #mesondefine _FILE_OFFSET_BITS
 
@@ -57,18 +54,6 @@
 /* IEEE Std 1003.1. */
 #mesondefine _POSIX_C_SOURCE
 
-/* POSIX and XPG 7th edition */
-#mesondefine _XOPEN_SOURCE
-
-/* TODO: Still needed? XPG things and X/Open Unix extensions. */
-#mesondefine _XOPEN_SOURCE_EXTENDED
-
-/* ISO C, POSIX, and 4.3BSD things. */
-#mesondefine _BSD_SOURCE
-
-/* ISO C, POSIX, and SVID things. */
-#mesondefine _SVID_SOURCE
-
 /* Define to 1 to force use of MinGW provided C99 *printf over msvcrt */
 #mesondefine __USE_MINGW_ANSI_STDIO
 

configure.ac

@@ -297,10 +297,6 @@ int foo() { return my_array[0]; }
     AC_DEFINE([_ISOC11_SOURCE], [1], [Extensions to ISO C99 from ISO C11.])
     AC_DEFINE([_POSIX_SOURCE], [1], [IEEE Std 1003.1.])
     AC_DEFINE([_POSIX_C_SOURCE], [200809L], [IEEE Std 1003.1.])
-    AC_DEFINE([_XOPEN_SOURCE], [700], [POSIX and XPG 7th edition])
-    AC_DEFINE([_XOPEN_SOURCE_EXTENDED], [1], [XPG things and X/Open Unix extensions.])
-    AC_DEFINE([_BSD_SOURCE], [1], [ISO C, POSIX, and 4.3BSD things.])
-    AC_DEFINE([_SVID_SOURCE], [1], [ISO C, POSIX, and SVID things.])
 
     AC_ARG_WITH(packagedir,
       AS_HELP_STRING([--with-packagedir=DIR],

meson.build

@@ -347,10 +347,6 @@ windows_version_test = '''
             ['_ISOC11_SOURCE',              1], # Extensions to ISO C99 from ISO C11
             ['_POSIX_SOURCE',               1], # IEEE Std 1003.1
             ['_POSIX_C_SOURCE',             '200809L'], #IEEE Std 1003.1
-            ['_XOPEN_SOURCE',               700], # POSIX and XPG 7th edition
-            ['_XOPEN_SOURCE_EXTENDED',      1], # XPG things and X/Open Unix extensions
-            ['_BSD_SOURCE',                 1], # ISO C, POSIX, and 4.3BSD things
-            ['_SVID_SOURCE',                1], # ISO C, POSIX, and SVID things
         ]
 
         foreach d : mingw_defines