[PATCH] configure.ac: check for has_colors symbol in curses lib

[Lars Wendler <polynomial-c@gentoo.org>]

Otherwise zsh/curses module won't get built if ncurses was built with
separate tinfo lib.
One could still force-build the module but loading it later yields the
following error message:

  failed to load module `zsh/curses': /usr/lib64/zsh/5.7.1/zsh/curses.so:
  undefined symbol: COLORS

That is because the final linker call requires -lncurses(w) but it only
contains -ltinfo(w).

Reported-by: Tetja Rediske <tetja@tetja.de>
See-also: http://www.zsh.org/mla/users/2016/msg01097.html
Signed-off-by: Lars Wendler <polynomial-c@gentoo.org>
---
 configure.ac | 1 +
 1 file changed, 1 insertion(+)

diff --git a/configure.ac b/configure.ac
index 8fd4d452f..9623133f0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -816,6 +816,7 @@ AC_SEARCH_LIBS(tgetent, [$termcap_curses_order],
 This is probably a library called 'curses' or 'ncurses'.  You may
 need to install a package called 'curses-devel' or 'ncurses-devel' on your
 system."], 255))
+AC_SEARCH_LIBS(has_colors, [$termcap_curses_order])
 AC_CHECK_HEADERS(curses.h, [],
 [AC_CACHE_CHECK(for Solaris 8 curses.h mistake, ac_cv_header_curses_solaris,
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <curses.h>]], [[]])],[ac_cv_header_curses_h=yes
-- 
2.24.1