binutils: Add lib output

Some packages depend on libbfd. This prevents them from having all of
binutils in their closure (which is 29 MiB).

pkgs/development/tools/misc/binutils/no-plugins.patch

@@ -0,0 +1,19 @@
+diff -ru binutils-2.27-orig/bfd/plugin.c binutils-2.27/bfd/plugin.c
+--- binutils-2.27-orig/bfd/plugin.c	2016-10-14 17:46:30.791315555 +0200
++++ binutils-2.27/bfd/plugin.c	2016-10-14 17:46:38.583298765 +0200
+@@ -333,6 +333,7 @@
+   if (plugin_program_name == NULL)
+     return found;
+ 
++#if 0
+   plugin_dir = concat (BINDIR, "/../lib/bfd-plugins", NULL);
+   p = make_relative_prefix (plugin_program_name,
+ 			    BINDIR,
+@@ -364,6 +365,7 @@
+   free (p);
+   if (d)
+     closedir (d);
++#endif
+ 
+   return found;
+ }