config: add variables for more directories, %impersonate-linux-2.6?

* guix/config.scm.in: rename to guix/config.scm.in.in.

* guix/config.scm.in.in (%temp-directory, %libexecdir, %impersonate-linux-2.6?):
  new variables.

* configure.ac: Add option impersonate-linux-2.6-default and substitute
  it. Adjust from config.scm.in to config.scm.in.in.

* Makefile.am: Substitute libexecdir in guix/config.scm.in to produce final
  result, guix/config.scm.

Makefile.am

@@ -39,7 +39,8 @@ do_subst = $(SED)					\
   -e 's,[@]GUILE[@],$(GUILE),g'				\
   -e 's,[@]guilemoduledir[@],$(guilemoduledir),g'	\
   -e 's,[@]guileobjectdir[@],$(guileobjectdir),g'	\
-  -e 's,[@]localedir[@],$(localedir),g'
+  -e 's,[@]localedir[@],$(localedir),g' 		\
+  -e 's,[@]Libexecdir[@],$(libexecdir),g'
 
 scripts/guix: scripts/guix.in Makefile
 	$(AM_V_at)rm -f $@ $@-t
@@ -47,6 +48,9 @@ scripts/guix: scripts/guix.in Makefile
 	$(AM_V_GEN)$(do_subst) < "$(srcdir)/$@.in" > "$@-t"
 	$(AM_V_at)chmod a+x,a-w "$@-t" && mv -f "$@-t" "$@"
 
+guix/config.scm: guix/config.scm.in
+	$(AM_V_GEN)$(do_subst) < "$@.in" > "$@"
+
 nodist_noinst_SCRIPTS =				\
   pre-inst-env					\
   test-env

configure.ac

@@ -61,6 +61,17 @@ AC_ARG_WITH([selinux-policy-dir],
   [selinux_policydir='${datadir}/selinux/'])
 AC_SUBST([selinux_policydir])
 
+AC_ARG_WITH(impersonate-linux-2.6-default,
+  AC_HELP_STRING([--with-impersonate-linux-2.6-default],
+    [Whether builds should should impersonate linux 2.6 by default]),
+  [if test "x$withval" = "xyes"; then
+    impersonate_linux26="#t";
+   else
+    impersonate_linux26="#f";
+  fi],
+  [impersonate_linux26="#f"])
+AC_SUBST(impersonate_linux26)
+
 dnl Better be verbose.
 AC_MSG_CHECKING([for the store directory])
 AC_MSG_RESULT([$storedir])
@@ -306,7 +317,7 @@ AC_CONFIG_FILES([Makefile
                  po/guix/Makefile.in
                  po/packages/Makefile.in
                  etc/guix-daemon.cil
-                 guix/config.scm])
+                 guix/config.scm.in])
 
 AC_CONFIG_FILES([test-env:build-aux/test-env.in], [chmod +x test-env])
 AC_CONFIG_FILES([pre-inst-env:build-aux/pre-inst-env.in],

guix/config.scm.in.in

@@ -26,6 +26,8 @@
             %storedir
             %localstatedir
             %sysconfdir
+            %temp-directory
+            %libexecdir
 
             %store-directory
             %state-directory
@@ -37,7 +39,8 @@
             %liblz
             %gzip
             %bzip2
-            %xz))
+            %xz
+            %impersonate-linux-2.6?))
 
 ;;; Commentary:
 ;;;
@@ -64,9 +67,20 @@
 (define %localstatedir
   "@guix_localstatedir@")
 
+(define %temp-directory
+  (or (getenv "TMPDIR")
+      "/tmp"))
+
+(define %impersonate-linux-2.6?
+  (make-parameter @impersonate_linux26@))
+
 (define %sysconfdir
   "@guix_sysconfdir@")
 
+(define %libexecdir
+  (or (getenv "NIX_LIBEXEC_DIR")
+      "@Libexecdir@/guix"))
+
 (define %store-directory
   (or (and=> (getenv "NIX_STORE_DIR") canonicalize-path)
       %storedir))

guix/store/derivations.scm

@@ -317,7 +317,7 @@ name of each input with that input's hash."
                              (make-derivation-input hash sub-drvs))))
                         inputs)))
        (make-derivation outputs
-                        (sort inputs
+                        (sort (delete-duplicates inputs)
                               (lambda (drv1 drv2)
                                 (string<? (derivation-input-derivation drv1)
                                           (derivation-input-derivation drv2))))
@@ -353,7 +353,6 @@ long-running processes that know what they're doing.  Use with care!"
   ;; Typically this is meant to be used by Cuirass and Hydra, which can clear
   ;; caches when they start evaluating packages for another architecture.
   (invalidate-memoization! derivation->bytevector)
-  (invalidate-memoization! derivation-base16-hash)
 
   ;; FIXME: Comment out to work around <https://bugs.gnu.org/36487>.
   ;; (hash-clear! %derivation-cache)