tweaks: disable gnulib's workaround for the globbing of broken symlinks

Our use of globbing (for syntax files) doesn't care about such symlinks.

This avoids an unnecessary increase in size of eight kilobytes -- see
https://lists.gnu.org/archive/html/nano-devel/2017-03/msg00036.html.

configure.ac

@@ -32,6 +32,7 @@ gl_cv_func_printf_directive_n=yes
 gl_cv_func_printf_infinite_long_double=yes
 gl_cv_func_printf_long_double=yes
 gl_cv_func_snprintf_directive_n=yes
+gl_cv_glob_lists_symlinks=yes
 
 dnl Checks for programs.