daemon: Run 'guix perform-download' directly.

* nix/scripts/download.in: Remove.
* nix/local.mk (nodist_pkglibexec_SCRIPTS): Remove 'scripts/download'.
* config-daemon.ac: Don't output 'nix/scripts/download'.
* nix/libstore/builtins.cc (builtinDownload): Invoke 'guix
perform-download' directly.

config-daemon.ac

@@ -148,8 +148,6 @@ if test "x$guix_build_daemon" = "xyes"; then
   AC_SUBST([GUIX_TEST_ROOT])
 
   GUIX_CHECK_LOCALSTATEDIR
-  AC_CONFIG_FILES([nix/scripts/download],
-    [chmod +x nix/scripts/download])
   AC_CONFIG_FILES([nix/scripts/substitute],
     [chmod +x nix/scripts/substitute])
   AC_CONFIG_FILES([nix/scripts/offload],

nix/libstore/builtins.cc

@@ -39,7 +39,7 @@ static void builtinDownload(const Derivation &drv,
 
     const char *const argv[] =
       {
-	"download", drvPath.c_str(), output.c_str(), NULL
+	  "guix", "perform-download", drvPath.c_str(), output.c_str(), NULL
       };
 
     /* Tell the script what the store file name is, so that
@@ -50,7 +50,7 @@ static void builtinDownload(const Derivation &drv,
     /* Tell it about options such as "print-extended-build-trace".  */
     setenv("_NIX_OPTIONS", settings.pack().c_str(), 1);
 
-    const string program = settings.nixLibexecDir + "/download";
+    const string program = settings.guixProgram;
     execv(program.c_str(), (char *const *) argv);
 
     throw SysError(format("failed to run download program '%1%'") % program);

nix/local.mk

@@ -155,8 +155,7 @@ noinst_HEADERS =						\
 	           (write (get-string-all in) out)))))"
 
 nodist_pkglibexec_SCRIPTS =			\
-  %D%/scripts/substitute			\
-  %D%/scripts/download
+  %D%/scripts/substitute
 
 if BUILD_DAEMON_OFFLOAD
 

nix/scripts/download.in

-#!@SHELL@
-# A shorthand for "guix perform-download", for use by the daemon.
-
-if test "x$GUIX_UNINSTALLED" = "x"
-then
-    prefix="@prefix@"
-    exec_prefix="@exec_prefix@"
-    exec "@bindir@/guix" perform-download "$@"
-else
-    exec guix perform-download "$@"
-fi