Updates to QA scrdiff script to keep package configure macros in sync.

m4/package_ncurses.m4

@@ -0,0 +1,30 @@
+AC_DEFUN([AC_PACKAGE_NEED_NCURSES_H],
+  [ AC_CHECK_HEADERS([ncurses.h])
+    if test "$ac_cv_header_ncurses_h" != yes; then
+        echo
+        echo 'FATAL ERROR: could not find a valid ncurses header.'
+        echo 'Install the ncurses development package.'
+        exit 1
+    fi
+  ])
+
+AC_DEFUN([AC_PACKAGE_WANT_WORKING_LIBNCURSES],
+  [ AC_CHECK_LIB(ncurses, initscr,, [
+        echo
+        echo 'FATAL ERROR: could not find a valid ncurses library.'
+        echo 'Install the ncurses library package.'
+        exit 1
+    ])
+    AC_MSG_CHECKING([for bad glibc/ncurses header interaction])
+    libcurses="-lncurses"
+    LIBS="$LIBS $libcurses"
+    CFLAGS="$CFLAGS -D_GNU_SOURCE"
+    AC_TRY_LINK([
+#include <ncurses.h>
+#include <signal.h>],
+        [wgetch(stdscr);],
+        [enable_curses=yes; AC_MSG_RESULT([ok])],
+        [enable_curses=no; libcurses=""; AC_MSG_RESULT([disabling curses])])
+    AC_SUBST(enable_curses)
+    AC_SUBST(libcurses)
+  ])