configure: Make use of ncurses configurable

https://github.com/octo/liboping/pull/15

--- a/configure.ac
+++ b/configure.ac
@@ -206,27 +206,30 @@ AC_CHECK_FUNCS(nanosleep, [],
 		AC_MSG_ERROR(cannot find nanosleep)))
 AM_CONDITIONAL(BUILD_WITH_LIBRT, test "x$nanosleep_needs_rt" = "xyes")
 
-with_ncurses="no"
-AC_CHECK_HEADERS(ncursesw/ncurses.h ncurses.h, [with_ncurses="yes"], [])
-if test "x$with_ncurses" = "xyes"
-then
-	have_ncursesw="no"
-	have_ncurses="no"
-	NCURSES_LIB=""
+AC_ARG_WITH(ncurses, AS_HELP_STRING([--with-ncurses], [Build oping CLI tool with ncurses support]))
+AS_IF([test "x$with_ncurses" != "xno"], [
+	can_build_with_ncurses="no"
+	PKG_CHECK_MODULES([NCURSES], [ncursesw], [can_build_with_ncurses=yes], [
+		PKG_CHECK_MODULES([NCURSES], [ncurses], [can_build_with_ncurses=yes], [
+			AC_CHECK_LIB(ncursesw, mvwprintw, [NCURSES_LIBS="-lncursesw"; can_build_with_ncurses=yes], [
+				AC_CHECK_LIB(ncurses, mvwprintw, [NCURSES_LIBS="-lncurses"; can_build_with_ncurses=yes])
+			])
+		])
+	])
 
-	AC_CHECK_LIB(ncursesw, mvwprintw, [have_ncursesw="yes"], [have_ncursesw="no"])
-	AC_CHECK_LIB(ncurses, mvwprintw, [have_ncurses="yes"], [have_ncurses="no"])
+	AS_IF([test "x$can_build_with_ncurses" = "xyes"], [
+		AC_CHECK_HEADERS([ncursesw/curses.h ncursesw.h ncurses/curses.h ncurses.h], [can_build_with_ncurses=yes; break;], [can_build_with_ncurses=no])
+	])
 
-	if test "x$have_ncursesw" = "xyes"; then
-		NCURSES_LIB="-lncursesw"
-	else if test "x$have_ncurses" = "xyes"; then
-		NCURSES_LIB="-lncurses"
-	else
-		with_ncurses="no"
-	fi; fi
-	AC_SUBST(NCURSES_LIB)
-fi
-AM_CONDITIONAL(BUILD_WITH_LIBNCURSES, test "x$with_ncurses" = "xyes")
+	AS_IF([test "x$can_build_with_ncurses" = "xno" && test "x$with_ncurses" = "xyes"], [
+		AC_MSG_ERROR([ncurses not found but explicit enabled])
+	],
+	[test "x$can_build_with_ncurses" = "xno"], [
+		AC_MSG_WARN([Will not build oping with ncurses support -- no suiteable ncurses installation found])
+	])
+])
+
+AM_CONDITIONAL(BUILD_WITH_LIBNCURSES, test "x$with_ncurses" != "xno" && test "x$can_build_with_ncurses" = "xyes")
 
 AC_FUNC_STRERROR_R
 
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -43,8 +43,8 @@ if BUILD_WITH_LIBNCURSES
 bin_PROGRAMS += noping
 
 noping_SOURCES = oping.c
-noping_CPPFLAGS = $(AM_CPPFLAGS) -DUSE_NCURSES=1
-noping_LDADD = liboping.la -lm $(NCURSES_LIB)
+noping_CPPFLAGS = $(AM_CPPFLAGS) -DUSE_NCURSES=1 $(NCURSES_CFLAGS)
+noping_LDADD = liboping.la -lm $(NCURSES_LIBS)
 if BUILD_WITH_LIBRT
 noping_LDADD += -lrt
 endif
--- a/src/oping.c
+++ b/src/oping.c
@@ -82,11 +82,17 @@
 /* http://newsgroups.derkeiler.com/Archive/Rec/rec.games.roguelike.development/2010-09/msg00050.html */
 # define _X_OPEN_SOURCE_EXTENDED
 
-# if HAVE_NCURSESW_NCURSES_H
-#  include <ncursesw/ncurses.h>
-# elif HAVE_NCURSES_H
+#if defined HAVE_NCURSESW_CURSES_H
+#  include <ncursesw/curses.h>
+#elif defined HAVE_NCURSESW_H
+#  include <ncursesw.h>
+#elif defined HAVE_NCURSES_CURSES_H
+#  include <ncurses/curses.h>
+#elif defined HAVE_NCURSES_H
 #  include <ncurses.h>
-# endif
+#else
+#  error "SysV or X/Open-compatible Curses header file required"
+#endif
 
 # define OPING_GREEN 1
 # define OPING_YELLOW 2
--