Refactor Gerbil support

- Use the new Gambit support.
- Move files from $out to $out/gerbil.
- Use new Gerbil configuration and installation scripts.
- Move some fixups from preBuild to postPatch.
- Give up on previous failed attempts at using static libraries.
- Add support for compiling libraries written in Gerbil.
- Build using NIX_BUILD_CORES.
- Register all those things in all-packages.

pkgs/development/compilers/gerbil/unstable.nix

@@ -1,15 +1,34 @@
-{ stdenv, callPackage, fetchFromGitHub, gambit, gambit-unstable }:
+{ callPackage, fetchFromGitHub, gambit-unstable, gambit-support, coreutils, bash }:
 
 callPackage ./build.nix {
   version = "unstable-2020-02-27";
   git-version = "0.16-DEV-493-g1ffb74db";
-  #gambit = gambit-unstable;
-  gambit = gambit;
   src = fetchFromGitHub {
     owner = "vyzo";
     repo = "gerbil";
     rev = "1ffb74db5ffd49b4bad751586cef5e619c891d41";
     sha256 = "1szmdp8lvy5gpcwn5bpa7x383m6vywl35xa7hz9a5vs1rq4w2097";
   };
-  inherit stdenv;
+  inherit gambit-support;
+  gambit = gambit-unstable;
+  gambit-params = gambit-support.unstable-params;
+  configurePhase = ''
+    (cd src && ./configure \
+      --prefix=$out/gerbil \
+      --with-gambit=${gambit}/gambit \
+      --enable-libxml \
+      --enable-libyaml \
+      --enable-zlib \
+      --enable-sqlite \
+      --enable-mysql \
+      --enable-lmdb \
+      --enable-leveldb)
+  '';
+  installPhase = ''
+    runHook preInstall
+    mkdir -p $out/gerbil $out/bin
+    (cd src; ./install)
+    (cd $out/bin ; ln -s ../gerbil/bin/* .)
+    runHook postInstall
+  '';
 }