add a (slightly naive) packaging of osrm-backend and its missing dependencies

pkgs/servers/osrm-backend/4.5.0-openmp.patch

@@ -0,0 +1,18 @@
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index b6a40f9..87ca301 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -261,9 +261,10 @@ target_link_libraries(OSRM ${STXXL_LIBRARY})
+ target_link_libraries(osrm-extract ${STXXL_LIBRARY})
+ target_link_libraries(osrm-prepare ${STXXL_LIBRARY})
+ 
+-if(MINGW)
+-  # STXXL needs OpenMP library
+-  target_link_libraries(osrm-extract gomp)
++find_package(OpenMP)
++if (OPENMP_FOUND)
++    set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
++    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
+ endif()
+ 
+ find_package( OSMPBF REQUIRED )

pkgs/servers/osrm-backend/default.nix

@@ -0,0 +1,20 @@
+{stdenv, fetchurl, cmake, luabind, libosmpbf, stxxl, tbb, boost, expat, protobuf, bzip2, zlib}:
+
+stdenv.mkDerivation rec {
+  name = "osrm-backend-4.5.0";
+
+  src = fetchurl {
+    url = "https://github.com/Project-OSRM/osrm-backend/archive/v4.5.0.tar.gz";
+    sha256 = "af61e883051f2ecb73520ace6f17cc6da30edc413208ff7cf3d87992eca0756c";
+  };
+
+  patches = [ ./4.5.0-openmp.patch ];
+
+  buildInputs = [ cmake luabind luabind.lua libosmpbf stxxl tbb boost expat protobuf bzip2 zlib ];
+
+  meta = {
+    homepage = https://github.com/Project-OSRM/osrm-backend/wiki;
+    description = "Open Source Routing Machine computes shortest paths in a graph. It was designed to run well with map data from the Openstreetmap Project.";
+    license = stdenv.lib.licenses.bsd2;
+  };
+}