execline: wrap unconditionally; strip

I don't think there's any situation in which an unwrapped execlineb is
useful -- if you want to use different versions of the execlineb tool
it'll still prefer ones in PATH.  At the same time, implementing the
wrapper in this way, as a series of two derivations, meant that we
didn't get stdenv goodness for the wrapper.  This meant that, for
example, the wrapper was not stripped, and so execline ended up with
runtime dependencies on gcc and the Linux headers.  I don't want to
have to reimplement this sort of stuff when it's already in stdenv,
and so it makes much more sense to create the wrapper in the
mkDerivation call, where all of stdenv's normal magic will find it.

pkgs/tools/misc/execline/default.nix

@@ -1,85 +1,49 @@
 { lib, skawarePackages
 # for execlineb-with-builtins
 , coreutils, gnugrep, writeScriptBin, runCommand, runCommandCC
-# Whether to wrap bin/execlineb to have the execline tools on its PATH.
-, execlineb-with-builtins ? true
 }:
 
 with skawarePackages;
 
-let
-  outputs = [ "bin" "lib" "dev" "doc" "out" ];
-
-  execline =
-    buildPackage {
-      pname = "execline";
-      version = "2.5.3.0";
-      sha256 = "0czdrv9m8mnx94nf28dafij6z03k4mbhbs6hccfaardfd5l5q805";
-
-      description = "A small scripting language, to be used in place of a shell in non-interactive scripts";
-
-      inherit outputs;
-
-      # TODO: nsss support
-      configureFlags = [
-        "--libdir=\${lib}/lib"
-        "--dynlibdir=\${lib}/lib"
-        "--bindir=\${bin}/bin"
-        "--includedir=\${dev}/include"
-        "--with-sysdeps=${skalibs.lib}/lib/skalibs/sysdeps"
-        "--with-include=${skalibs.dev}/include"
-        "--with-lib=${skalibs.lib}/lib"
-        "--with-dynlib=${skalibs.lib}/lib"
-      ];
+buildPackage {
+  pname = "execline";
+  version = "2.5.3.0";
+  sha256 = "0czdrv9m8mnx94nf28dafij6z03k4mbhbs6hccfaardfd5l5q805";
 
-      postInstall = ''
-        # remove all execline executables from build directory
-        rm $(find -type f -mindepth 1 -maxdepth 1 -executable)
-        rm libexecline.*
+  description = "A small scripting language, to be used in place of a shell in non-interactive scripts";
 
-        mv doc $doc/share/doc/execline/html
-        mv examples $doc/share/doc/execline/examples
-      '';
-
-    };
+  outputs = [ "bin" "lib" "dev" "doc" "out" ];
 
-  # A wrapper around execlineb, which provides all execline
-  # tools on `execlineb`’s PATH.
-  # It is implemented as a C script, because on non-Linux,
-  # nested shebang lines are not supported.
-  execlineb-with-builtins-drv = runCommandCC "execlineb" {} ''
-    mkdir -p $out/bin
+  # TODO: nsss support
+  configureFlags = [
+    "--libdir=\${lib}/lib"
+    "--dynlibdir=\${lib}/lib"
+    "--bindir=\${bin}/bin"
+    "--includedir=\${dev}/include"
+    "--with-sysdeps=${skalibs.lib}/lib/skalibs/sysdeps"
+    "--with-include=${skalibs.dev}/include"
+    "--with-lib=${skalibs.lib}/lib"
+    "--with-dynlib=${skalibs.lib}/lib"
+  ];
+
+  postInstall = ''
+    # remove all execline executables from build directory
+    rm $(find -type f -mindepth 1 -maxdepth 1 -executable)
+    rm libexecline.*
+
+    mv doc $doc/share/doc/execline/html
+    mv examples $doc/share/doc/execline/examples
+
+    mv $bin/bin/execlineb $bin/bin/.execlineb-wrapped
     cc \
       -O \
       -Wall -Wpedantic \
-      -D 'EXECLINEB_PATH()="${execline}/bin/execlineb"' \
-      -D 'EXECLINE_BIN_PATH()="${execline}/bin"' \
+      -D "EXECLINEB_PATH()=\"$bin/bin/.execlineb-wrapped\"" \
+      -D "EXECLINE_BIN_PATH()=\"$bin/bin\"" \
       -I "${skalibs.dev}/include" \
       -L "${skalibs.lib}/lib" \
-      -l"skarnet" \
-      -o "$out/bin/execlineb" \
+      -lskarnet \
+      -o "$bin/bin/execlineb" \
       ${./execlineb-wrapper.c}
   '';
-
-
-  # the original execline package, with bin/execlineb overwritten
-  execline-with-builtins = runCommand "my-execline"
-    (execline.drvAttrs // {
-      preferLocalBuild = true;
-      allowSubstitutes = false;
-    })
-    # copy every output and just overwrite the execlineb binary in $bin
-    ''
-      ${lib.concatMapStringsSep "\n"
-        (output: ''
-          cp -r ${execline.${output}} "''$${output}"
-          chmod --recursive +w "''$${output}"
-        '')
-        outputs}
-      install ${execlineb-with-builtins-drv}/bin/execlineb $bin/bin/execlineb
-    '';
-
-in
-  if execlineb-with-builtins
-  then execline-with-builtins
-  else execline
+}

pkgs/tools/misc/execline/execlineb-wrapper.c

@@ -1,3 +1,10 @@
+/*
+ * A wrapper around execlineb, which provides all execline
+ * tools on execlineb’s PATH.
+ * It is implemented as a C program, because on non-Linux,
+ * nested shebang lines are not supported.
+ */
+
 #include <stdlib.h>
 #include <string.h>