diff --git a/pkgs/development/tools/rtags/default.nix b/pkgs/development/tools/rtags/default.nix
index 39ee3179e9c4..1825bbe81c30 100644
--- a/pkgs/development/tools/rtags/default.nix
+++ b/pkgs/development/tools/rtags/default.nix
@@ -1,17 +1,12 @@
-{ stdenv, lib, fetchgit, cmake, llvmPackages, openssl, writeScript, apple_sdk, bash, emacs }:
+{ stdenv, lib, fetchgit, cmake, llvmPackages, openssl, writeScript, apple_sdk, bash, emacs, pkgconfig }:
 
 stdenv.mkDerivation rec {
   name = "rtags-${version}";
   version = "2.12";
 
-  buildInputs = [ cmake llvmPackages.llvm openssl llvmPackages.clang emacs ]
+  buildInputs = [ cmake llvmPackages.llvm openssl llvmPackages.clang emacs pkgconfig ]
     ++ lib.optionals stdenv.isDarwin [ apple_sdk.libs.xpc apple_sdk.frameworks.CoreServices ];
 
-  preConfigure = ''
-    export LIBCLANG_CXXFLAGS="-isystem ${llvmPackages.clang.cc}/include $(llvm-config --cxxflags) -fexceptions" \
-           LIBCLANG_LIBDIR="${llvmPackages.clang.cc}/lib"
-  '';
-
 
   src = fetchgit {
     rev = "refs/tags/v${version}";
@@ -25,6 +20,11 @@ stdenv.mkDerivation rec {
     '';
   };
 
+  preConfigure = ''
+    export LIBCLANG_CXXFLAGS="-isystem ${llvmPackages.clang.cc}/include $(llvm-config --cxxflags) -fexceptions" \
+           LIBCLANG_LIBDIR="${llvmPackages.clang.cc}/lib"
+  '';
+
   enableParallelBuilding = true;
 
   meta = {
diff --git a/pkgs/top-level/emacs-packages.nix b/pkgs/top-level/emacs-packages.nix
index 5c50fe383bb9..4734b51046fd 100644
--- a/pkgs/top-level/emacs-packages.nix
+++ b/pkgs/top-level/emacs-packages.nix
@@ -269,8 +269,11 @@ let
 
   rtags = melpaBuild rec {
     pname = "rtags";
-    version = "2.0"; # really, it's some arbitrary git hash
+    version = "2.12";
     src = external.rtags.src;
+
+    configurePhase = ":";
+
     propagatedUserEnvPkgs = [ external.rtags ];
     fileSpecs = [ "src/*.el" ];
     inherit (external.rtags) meta;