meson.build: Support ncurses on MacOS and OpenBSD

MacOS provides header files for curses 5.7 with support
for wide characters, but requires _XOPEN_SOURCE_EXTENDED=1
to activate that.

By default those old header files are used even if there
is a newer Homebrew installation of ncurses 6.2 available.

Change also the old macro definition of NCURSES_WIDECHAR
and set it to 1 like it is done in newer versions of
curses.h when _XOPEN_SOURCE_EXTENDED=1 is defined.

OpenBSD has the same version of ncurses and needs the same fix.

Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Tested-by: Brad Smith <brad@comstyle.com>
Message-Id: <20211117205355.1392292-1-sw@weilnetz.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

meson.build

@@ -679,6 +679,9 @@ iconv = not_found
 curses = not_found
 if have_system and not get_option('curses').disabled()
   curses_test = '''
+    #if defined(__APPLE__) || defined(__OpenBSD__)
+    #define _XOPEN_SOURCE_EXTENDED 1
+    #endif
     #include <locale.h>
     #include <curses.h>
     #include <wchar.h>
@@ -702,7 +705,7 @@ if have_system and not get_option('curses').disabled()
     endif
   endforeach
   msg = get_option('curses').enabled() ? 'curses library not found' : ''
-  curses_compile_args = ['-DNCURSES_WIDECHAR']
+  curses_compile_args = ['-DNCURSES_WIDECHAR=1']
   if curses.found()
     if cc.links(curses_test, args: curses_compile_args, dependencies: [curses])
       curses = declare_dependency(compile_args: curses_compile_args, dependencies: [curses])

ui/curses.c

@@ -38,6 +38,10 @@
 #include "ui/input.h"
 #include "sysemu/sysemu.h"
 
+#if defined(__APPLE__) || defined(__OpenBSD__)
+#define _XOPEN_SOURCE_EXTENDED 1
+#endif
+
 /* KEY_EVENT is defined in wincon.h and in curses.h. Avoid redefinition. */
 #undef KEY_EVENT
 #include <curses.h>