Fix `canonicalize_file_name' replacement handling when cross-compiling.
Without this patch, we end up with:

  ./.libs/libguile-2.0.so: undefined reference to `rpl_canonicalize_file_name'

See <http://hydra.nixos.org/build/2765567> for details.

index 69b3f4c..3c4c5ee 100644
--- a/m4/canonicalize.m4
+++ b/m4/canonicalize.m4
@@ -16,8 +16,11 @@ AC_DEFUN([gl_FUNC_CANONICALIZE_FILENAME_MODE],
   AC_REQUIRE([gl_FUNC_REALPATH_WORKS])
   if test $ac_cv_func_canonicalize_file_name = no; then
     HAVE_CANONICALIZE_FILE_NAME=0
-  elif test "$gl_cv_func_realpath_works" != yes; then
-    REPLACE_CANONICALIZE_FILE_NAME=1
+  else
+    case "$gl_cv_func_realpath_works" in
+      *yes) ;;
+      *)    REPLACE_CANONICALIZE_FILE_NAME=1 ;;
+    esac
   fi
 ])
 
@@ -30,12 +33,21 @@ AC_DEFUN([gl_CANONICALIZE_LGPL],
     HAVE_CANONICALIZE_FILE_NAME=0
     if test $ac_cv_func_realpath = no; then
       HAVE_REALPATH=0
-    elif test "$gl_cv_func_realpath_works" != yes; then
-      REPLACE_REALPATH=1
+    else
+      case "$gl_cv_func_realpath_works" in
+	*yes) ;;
+	*)    REPLACE_REALPATH=1 ;;
+      esac
     fi
-  elif test "$gl_cv_func_realpath_works" != yes; then
-    REPLACE_CANONICALIZE_FILE_NAME=1
-    REPLACE_REALPATH=1
+  else
+    case "$gl_cv_func_realpath_works" in
+      *yes)
+        ;;
+      *)
+        REPLACE_CANONICALIZE_FILE_NAME=1
+        REPLACE_REALPATH=1
+        ;;
+    esac
   fi
 ])


Now, work around a second bug: fix default value when cross-compiling
for GNU/Hurd.

index 69b3f4c..111ddf8 100644
--- a/m4/canonicalize.m4
+++ b/m4/canonicalize.m4
@@ -95,7 +95,7 @@ AC_DEFUN([gl_FUNC_REALPATH_WORKS],
      [gl_cv_func_realpath_works=no],
      [case "$host_os" in
                 # Guess yes on glibc systems.
-        *-gnu*) gl_cv_func_realpath_works="guessing yes" ;;
+        *gnu*)  gl_cv_func_realpath_works="guessing yes" ;;
                 # If we don't know, assume the worst.
         *)      gl_cv_func_realpath_works="guessing no" ;;
       esac