From b02cb7e0bcf0ae747355b988b45900ed81538823 Mon Sep 17 00:00:00 2001
From: Geert Janssens <geert@kobaltwit.be>
Date: Thu, 19 Apr 2018 15:29:07 +0200
Subject: [PATCH] Fix guile executable detection on early 2.0.x guile versions

Querying guile-config for the executable name was only introduced in guile 2.0.12.
If it works it's the most reliable method in environments with more than one guile
executable. If it doesn't work fall back to path detection, assuming the executable
name is just 'guile'. If that's incorrect it's up to the caller to explicitly
specify the path to the right guile executable.
---
 configure.ac | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/configure.ac b/configure.ac
index 664c0fa1a..0720ad66f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1705,19 +1705,20 @@ else
   if test -n "$GUILE_CONFIG" ; then
     if test x"$GUILE" = xyes; then
       AC_MSG_CHECKING([for guile executable])
-      if $GUILE_CONFIG info guile > /dev/null 2>&1; then
-        GUILE="`$GUILE_CONFIG info guile`"
+      # Try extracting it via guile-config first. If it's defined there it's the most reliable result
+      GUILE="`$GUILE_CONFIG info guile 2>/dev/null`"
+      if test -n "$GUILE";  then
         AC_MSG_RESULT([$GUILE])
       else
         AC_MSG_RESULT([not in guile-config, constructing path])
         AC_MSG_CHECKING([for guile bindir])
         guile_bindir="`$GUILE_CONFIG info bindir`"
         AC_MSG_RESULT([$guile_bindir])
-        GUILE=$guile_bindir/guile
-        if ! test -f "$GUILE" ; then
-          GUILE=
-          AC_PATH_PROG(GUILE, guile)
-        fi
+        GUILE="$guile_bindir/guile"
+      fi
+      if ! test -f "$GUILE" ; then
+        GUILE=
+        AC_PATH_PROG(GUILE, guile)
       fi
     fi