boomerang: Fix prefix in dlopen().

We already have the correct library dir in our search path, so we don't need to
prepend lib/ again.

pkgs/development/tools/boomerang/default.nix

···
     install -vD boomerang "$out/bin/boomerang"
   '';
 
+  patches = [ ./dlopen_path.patch ];
+
   src = fetchgit {
     url = "git://github.com/aszlig/boomerang.git";
     rev = "d0b147a5dfc915a5fa8fe6c517e66a049a37bf22";

pkgs/development/tools/boomerang/dlopen_path.patch

···
+diff --git a/loader/BinaryFileFactory.cpp b/loader/BinaryFileFactory.cpp
+index 889a4ed..ca86765 100644
+--- a/loader/BinaryFileFactory.cpp
++++ b/loader/BinaryFileFactory.cpp
+@@ -109,7 +109,7 @@ BinaryFile* BinaryFileFactory::getInstanceFor( const char *sName ) {
+ 	
+ // Load the specific loader library
+ #ifndef _WIN32		// Cygwin, Unix/Linux
+-	libName = std::string("lib/lib") + libName;
++	libName = std::string("lib") + libName;
+ #ifdef	__CYGWIN__
+ 	libName += ".dll";		// Cygwin wants .dll, but is otherwise like Unix
+ #else