patch 8.2.0988: getting directory contents is always case sorted

Problem:    Getting directory contents is always case sorted.
Solution:   Add sort options and v:collate. (Christian Brabandt, closes #6229)
diff --git a/src/configure.ac b/src/configure.ac
index dccf3dc..0543918 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -3739,7 +3739,7 @@
 	getpwent getpwnam getpwuid getrlimit gettimeofday localtime_r lstat \
 	memset mkdtemp nanosleep opendir putenv qsort readlink select setenv \
 	getpgid setpgid setsid sigaltstack sigstack sigset sigsetjmp sigaction \
-	sigprocmask sigvec strcasecmp strerror strftime stricmp strncasecmp \
+	sigprocmask sigvec strcasecmp strcoll strerror strftime stricmp strncasecmp \
 	strnicmp strpbrk strptime strtol tgetent towlower towupper iswupper \
 	tzset usleep utime utimes mblen ftruncate unsetenv posix_openpt)
 AC_FUNC_SELECT_ARGTYPES