Make configure check for ncurses header files

First ncursesw/ncurses.h, then ncurses/ncurses.h, and finally ncurses.h.
Also include ncurses.h by default instead of curses.h. On most system
ncurses.h should be a symlink to curses.h and this will avoid the
problem of including a non-ncurses header file.

This should fix systems like Solaris who ships their own version of
/usr/include/curses.h that is incompatible with ncurses.

Reported by SungHyun Nam.

NEWS

@@ -9,6 +9,7 @@ Improvements:
  - F5 also refreshes the current view.
  - Allow line graphics to be disabled with new line-graphics option.
  - Also include the reference names when searching.
+ - Configure: check for the ncurses header files.
 
 Bug fixes:
 

configure.ac

@@ -1,13 +1,23 @@
-AC_INIT([tig], [0],
-	[Jonas Fonseca <fonseca@diku.dk>],
-	[tig])
+AC_INIT([tig], [0], [Jonas Fonseca <fonseca@diku.dk>], [tig])
 
 AC_LANG([C])
 AC_CONFIG_HEADER(config.h)
 AC_CONFIG_SRCDIR(tig.c)
 
-AC_SEARCH_LIBS([wclear], [ncursesw ncurses curses], [],
-	       [AC_ERROR([curses not found])])
+cursed=no
+AC_CHECK_HEADERS([ncursesw/ncurses.h],
+		 [AC_SEARCH_LIBS([initscr], [ncursesw], [cursed=yes])])
+case "$cursed" in "no")
+	AC_CHECK_HEADERS([ncurses/ncurses.h ncurses.h],
+			 [AC_SEARCH_LIBS([wclear], [ncurses], [cursed=yes])])
+
+	case "$cursed" in "no")
+		AC_ERROR([ncurses not found])
+	esac
+
+	AC_MSG_WARN([The found ncurses library does not support wide-char.])
+	AC_MSG_WARN([This means that tig will not correctly render UTF-8.])
+esac
 
 AM_ICONV
 
@@ -26,9 +36,3 @@ AC_CHECK_PROGS(DOCBOOK2PDF, [docbook2pdf false])
 
 AC_CONFIG_FILES([config.make])
 AC_OUTPUT
-
-case "$LIBS" in
-*-lncursesw*) ;;
-*) AC_MSG_RESULT([NOTE: The found ncurses library does not support wide-char.])
-   AC_MSG_RESULT([NOTE: This means that tig will not correctly render UTF-8])
-esac

tig.c

@@ -45,7 +45,15 @@
 /* ncurses(3): Must be defined to have extended wide-character functions. */
 #define _XOPEN_SOURCE_EXTENDED
 
-#include <curses.h>
+#ifdef HAVE_NCURSESW_NCURSES_H
+#include <ncursesw/ncurses.h>
+#else
+#ifdef HAVE_NCURSES_NCURSES_H
+#include <ncurses/ncurses.h>
+#else
+#include <ncurses.h>
+#endif
+#endif
 
 #if __GNUC__ >= 3
 #define __NORETURN __attribute__((__noreturn__))