Revert "do not define internal libc macros"

another attempt at fixing macos

This reverts commit be5bf3e.

src/nnn.c

@@ -29,12 +29,6 @@
  */
 
 #define _FILE_OFFSET_BITS 64 /* Support large files on 32-bit glibc */
-#define _XOPEN_SOURCE_EXTENDED
-#undef  _XOPEN_SOURCE
-#define _XOPEN_SOURCE 700L
-#ifndef NCURSES_WIDECHAR
-#define NCURSES_WIDECHAR 1
-#endif
 
 #if defined(__linux__) || defined(MINGW) || defined(__MINGW32__) \
 	|| defined(__MINGW64__) || defined(__CYGWIN__)
@@ -65,6 +59,19 @@
 #endif
 #include <sys/wait.h>
 
+#ifdef __linux__ /* Fix failure due to mvaddnwstr() */
+#ifndef NCURSES_WIDECHAR
+#define NCURSES_WIDECHAR 1
+#endif
+#elif defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) \
+	|| defined(__APPLE__) || defined(__sun)
+#ifndef _XOPEN_SOURCE_EXTENDED
+#define _XOPEN_SOURCE_EXTENDED
+#endif
+#endif
+#ifndef __USE_XOPEN /* Fix wcswidth() failure, ncursesw/curses.h includes whcar.h on Ubuntu 14.04 */
+#define __USE_XOPEN
+#endif
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -94,6 +101,9 @@
 #include <unistd.h>
 #include <stddef.h>
 #include <stdalign.h>
+#ifndef __USE_XOPEN_EXTENDED
+#define __USE_XOPEN_EXTENDED 1
+#endif
 #include <ftw.h>
 #include <pwd.h>
 #include <grp.h>