Capture the path to `guile', when available.

src/script/Makefile.am

@@ -1,15 +1,19 @@
-EXTRA_DIST = \
-  hydra-control \
-  $(bin_SCRIPTS)
+EXTRA_DIST =					\
+  $(distributable_scripts)			\
+  hydra-control					\
+  hydra-eval-guile-jobs.in
 
-bin_SCRIPTS = \
-  hydra-init \
-  hydra-build \
-  hydra-evaluator \
-  hydra-eval-guile-jobs \
-  hydra-queue-runner \
-  hydra-server \
-  hydra-update-gc-roots \
-  nix-prefetch-git \
-  nix-prefetch-bzr \
+distributable_scripts =				\
+  hydra-init					\
+  hydra-build					\
+  hydra-evaluator				\
+  hydra-queue-runner				\
+  hydra-server					\
+  hydra-update-gc-roots				\
+  nix-prefetch-git				\
+  nix-prefetch-bzr				\
   nix-prefetch-hg
+
+bin_SCRIPTS =					\
+  $(distributable_scripts)			\
+  hydra-eval-guile-jobs

src/script/hydra-eval-guile-jobs.in

@@ -8,7 +8,7 @@ main="(module-ref (resolve-interface '(hydra-eval-guile-jobs)) 'eval-guile-jobs)
 unset GUILE_LOAD_PATH
 unset GUILE_LOAD_COMPILED_PATH
 
-exec ${GUILE:-guile} --no-auto-compile   \
+exec ${GUILE:-@GUILE@} --no-auto-compile   \
   -l "$0" -c "(apply $main (cdr (command-line)))" "$@"
 !#
 ;;; Copyright (C) 2012  Ludovic Courtès <ludo@gnu.org>