mimalloc: un-break dynamic linking

Previous versions of the build assumed libmimalloc.so would be a hard
copy of mimalloc-secure.so iff secureBuild == true, but in 1.1.0 and
later it seems libmimalloc.so is a symlink to the -secure variant. This
apparently rectifies some behavior I noticed that was strange
previously.

This breakage wasn't caught because the 1.1.0 update was automatic in
5596317d4; there should be a checkPhase to ensure this doesn't happen
again...

Signed-off-by: Austin Seipp <aseipp@pobox.com>

pkgs/development/libraries/mimalloc/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchFromGitHub, cmake
+{ stdenv, fetchFromGitHub, cmake, ninja
 , secureBuild ? true
 }:
 
@@ -6,32 +6,33 @@ let
   soext = stdenv.hostPlatform.extensions.sharedLibrary;
 in
 stdenv.mkDerivation rec {
-  name    = "mimalloc-${version}";
+  pname   = "mimalloc";
   version = "1.1.0";
 
   src = fetchFromGitHub {
     owner  = "microsoft";
-    repo   = "mimalloc";
+    repo   = pname;
     rev    = "refs/tags/v${version}";
     sha256 = "1i8pwzpcmbf7dxncb984xrnczn1737xqhf1jaizlyw0k1hpiam4v";
   };
 
-  nativeBuildInputs = [ cmake ];
+  nativeBuildInputs = [ cmake ninja ];
   enableParallelBuilding = true;
-
   cmakeFlags = stdenv.lib.optional secureBuild [ "-DMI_SECURE=ON" ];
 
   postInstall = ''
+    # first, install headers, that's easy
     mkdir -p $dev
     mv $out/lib/*/include $dev/include
 
-    rm -f $out/lib/libmimalloc*${soext} # weird duplicate
-
+    # move everything else into place
     mv $out/lib/*/libmimalloc*${soext} $out/lib/libmimalloc${soext}
     mv $out/lib/*/libmimalloc*.a       $out/lib/libmimalloc.a
     mv $out/lib/*/mimalloc*.o          $out/lib/mimalloc.o
 
-    rm -rf $out/lib/mimalloc-*
+    # remote duplicate dir. FIXME: try to fix the .cmake file distribution
+    # so we can re-use it for dependencies...
+    rm -r $out/lib/mimalloc-1.0/
   '';
 
   outputs = [ "out" "dev" ];