musl-obstack: init at 1.2.2

in service of getting elfutils building against musl-libc, this library
is an extraction of the obstack functions from glibc/libiberty. this is
the approach taken by void and alpine linux.

pkgs/os-specific/linux/musl-obstack/default.nix

···
+{ lib, stdenv, fetchFromGitHub, autoreconfHook, pkg-config }:
+
+stdenv.mkDerivation rec {
+  pname = "musl-obstack";
+  version = "1.2.2";
+
+  src = fetchFromGitHub {
+    owner = "void-linux";
+    repo = "musl-obstack";
+    rev = "v${version}";
+    sha256 = "v0RTnrqAmJfOeGsJFc04lqFR8QZhYiLyvy8oRYiuC80=";
+  };
+
+  nativeBuildInputs = [ autoreconfHook pkg-config ];
+
+  enableParallelBuilding = true;
+
+  meta = with lib; {
+    homepage = "https://github.com/void-linux/musl-obstack";
+    description =
+      "An extraction of the obstack functions and macros from GNU libiberty for use with musl-libc";
+    platforms = platforms.linux;
+    license = licenses.lgpl21Plus;
+    maintainers = [ maintainers.pjjw ];
+  };
+}

pkgs/top-level/all-packages.nix

···
   musl = callPackage ../os-specific/linux/musl { };
 
   musl-fts = callPackage ../os-specific/linux/musl-fts { };
+  musl-obstack = callPackage ../os-specific/linux/musl-obstack { };
 
   nushell = callPackage ../shells/nushell {
     inherit (darwin.apple_sdk.frameworks) AppKit Security;