Use pkg-config to detect ncurses

Ncurses provides a pkg-config module which could be used here. If not
available we fall back to the old detection heuristic.

Signed-off-by: Justin Lecher <jlec@gentoo.org>

configure.ac

@@ -36,16 +36,20 @@ AC_ARG_WITH([ncursesw],
             AC_HELP_STRING([--with-ncursesw], [compile/link with wide-char ncurses library @<:@default@:>@]),
             [ncurses=ncursesw])
 if test "$ncurses" = "auto" -o "$ncurses" = "ncursesw"; then
-  AC_CHECK_LIB([ncursesw],
+  PKG_CHECK_MODULES([NCURSES], [ncursesw], [LIBS="$LIBS $NCURSES_LIBS"; ncurses=ncursesw],
+    [AC_CHECK_LIB([ncursesw],
                  [initscr],
                  [LIBS="$LIBS -lncursesw"; ncurses=ncursesw],
                  [ncurses=ncurses])
+    ])
 fi
 if test "$ncurses" = "ncurses"; then
-  AC_CHECK_LIB([ncurses],
+  PKG_CHECK_MODULES([NCURSES], [ncurses], [LIBS="$LIBS $NCURSES_LIBS"],
+    [AC_CHECK_LIB([ncurses],
                  [initscr],
                  [LIBS="$LIBS -lncurses"],
                  [AC_MSG_ERROR(ncurses library is required)])
+    ])
 fi