mariadb: Patch to compile on OS X.

* perl is required at build time on darwin. Copied from the
  mysql/5.5.x.nix

* CMake on darwin creates shared libraries with relative 'install_name'
  paths which are made absolute by fixDarwinDylibNames.

  See http://answers.opencv.org/question/4134/cmake-install_name_tool-absolute-path-for-library/

* The asm patch was needed to compile on darwin, though I do not
  understand what is going on. Error before the patch:

  [ 15%] Building C object mysys/CMakeFiles/mysys.dir/my_context.c.o
  .../nix-build-mariadb-10.0.13.drv-1/mariadb-10.0.13/mysys/my_context.c:207:Unknown pseudo-op: .cfi_escape
  .../nix-build-mariadb-10.0.13.drv-1/mariadb-10.0.13/mysys/my_context.c:207:Rest of line ignored. 1st junk character valued 48 (0).
  make[2]: *** [mysys/CMakeFiles/mysys.dir/my_context.c.o] Error 1

pkgs/servers/sql/mariadb/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchurl, cmake, ncurses, openssl, bison, boost, libxml2, libaio, judy, libevent, groff }:
+{ stdenv, fetchurl, cmake, ncurses, openssl, bison, boost, libxml2, libaio, judy, libevent, groff, perl, fixDarwinDylibNames }:
 
 stdenv.mkDerivation rec {
   name = "mariadb-${version}";
@@ -9,12 +9,25 @@ stdenv.mkDerivation rec {
     sha256 = "039wz89vs03a27anpshj5xaqknm7cqi7mrypvwingqkq26ns0mhs";
   };
 
-  buildInputs = [ cmake ncurses openssl bison boost libxml2 libaio judy libevent groff ];
+  buildInputs = [ cmake ncurses openssl bison boost libxml2 judy libevent groff ]
+     ++ stdenv.lib.optional (!stdenv.isDarwin) libaio
+     ++ stdenv.lib.optionals stdenv.isDarwin [ perl fixDarwinDylibNames ];
+
+  patches = stdenv.lib.optional stdenv.isDarwin ./my_context_asm.patch;
 
   cmakeFlags = [ "-DWITH_READLINE=yes" "-DWITH_EMBEDDED_SERVER=yes" "-DINSTALL_SCRIPTDIR=bin" ];
 
   enableParallelBuilding = true;
 
+  prePatch = ''
+    substituteInPlace cmake/libutils.cmake \
+      --replace /usr/bin/libtool libtool
+  '';
+  postInstall = ''
+    substituteInPlace $out/bin/mysql_install_db \
+      --replace basedir=\"\" basedir=\"$out\"
+  '';
+
   passthru.mysqlVersion = "5.5";
 
   meta = {