libedit: add FreeBSD support

pkgs/development/libraries/libedit/default.nix

@@ -15,6 +15,9 @@ stdenv.mkDerivation rec {
     sed -i s/-lncurses/-lncursesw/g $out/lib/pkgconfig/libedit.pc
   '';
 
+  # taken from gentoo http://sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo-x86/dev-libs/libedit/files/
+  patches = [ ./freebsd.patch ./freebsd_weak_ref.patch ];
+
   configureFlags = "--enable-widec";
 
   propagatedBuildInputs = [ ncurses ];

pkgs/development/libraries/libedit/freebsd.patch

@@ -0,0 +1,13 @@
+diff --git a/src/chartype.h b/src/chartype.h
+index c35825c..be5aac0 100644
+--- a/src/chartype.h
++++ b/src/chartype.h
+@@ -44,7 +44,7 @@
+  * supports non-BMP code points without requiring UTF-16, but nothing
+  * seems to actually advertise this properly, despite Unicode 3.1 having
+  * been around since 2001... */
+-#if !defined(__NetBSD__) && !defined(__sun) && !(defined(__APPLE__) && defined(__MACH__))
++#if !defined(__NetBSD__) && !defined(__sun) && !(defined(__APPLE__) && defined(__MACH__)) && !defined(__DragonFly__) && !defined(__FreeBSD__)
+ #ifndef __STDC_ISO_10646__
+ /* In many places it is assumed that the first 127 code points are ASCII
+  * compatible, so ensure wchar_t indeed does ISO 10646 and not some other

pkgs/development/libraries/libedit/freebsd_weak_ref.patch

@@ -0,0 +1,20 @@
+--- libedit-20110709-3.0/src/vi.c.old	2011-07-11 18:21:16.000000000 +0000
++++ libedit-20110709-3.0/src/vi.c	2011-07-11 18:24:29.000000000 +0000
+@@ -918,7 +918,7 @@
+  * NB: posix implies that we should enter insert mode, however
+  * this is against historical precedent...
+  */
+-#ifdef __weak_reference
++#if defined(__weak_reference) && defined(__NetBSD__)
+ __weakref_visible char *my_get_alias_text(const char *)
+     __weak_reference(get_alias_text);
+ #endif
+@@ -926,7 +926,7 @@
+ /*ARGSUSED*/
+ vi_alias(EditLine *el, Int c)
+ {
+-#ifdef __weak_reference
++#if defined(__weak_reference) && defined(__NetBSD__)
+ 	char alias_name[3];
+ 	char *alias_text;
+