treewide: Remove gnat support.

See discussion in 6ac7b19c97.

pkgs/development/compilers/gnatboot/default.nix

@@ -1,48 +0,0 @@
-{stdenv, fetchurl}:
-
-stdenv.mkDerivation {
-  name = "gentoo-gnatboot-4.1";
-
-  src = if stdenv.system == "i686-linux" then
-    fetchurl {
-      url = "mirror://gentoo/distfiles/gnatboot-4.1-i386.tar.bz2";
-      sha256 = "0665zk71598204bf521vw68i5y6ccqarq9fcxsqp7ccgycb4lysr";
-    }
-    else if stdenv.system == "x86_64-linux" then
-    fetchurl {
-      url = "mirror://gentoo/distfiles/gnatboot-4.1-amd64.tar.bz2";
-      sha256 = "1li4d52lmbnfs6llcshlbqyik2q2q4bvpir0f7n38nagp0h6j0d4";
-    } else throw "Platform not supported";
-
-  dontStrip=1;
-
-  installPhase = ''
-    mkdir -p $out
-    cp -R * $out
-    set +e
-    for a in $out/bin/* ; do
-      patchelf --interpreter $(cat $NIX_CC/nix-support/dynamic-linker) \
-        --set-rpath $(cat $NIX_CC/nix-support/orig-libc)/lib:$(cat $NIX_CC/nix-support/orig-cc)/lib64:$(cat $NIX_CC/nix-support/orig-cc)/lib $a
-    done
-    set -e
-    mv $out/bin/gnatgcc_2wrap $out/bin/gnatgcc
-    ln -s $out/bin/gnatgcc $out/bin/gcc
-  '';
-
-  passthru = {
-    langC = true; /* TRICK for gcc-wrapper to wrap it */
-    langCC = false;
-    langFortran = false;
-    langAda = true;
-  };
-
-  meta = {
-    homepage = http://gentoo.org;
-    license = stdenv.lib.licenses.gpl3Plus;  # runtime support libraries are typically LGPLv3+
-    maintainers = [
-      stdenv.lib.maintainers.viric
-    ];
-    
-    platforms = stdenv.lib.platforms.linux;
-  };
-}