[m-rev.] diff: warn about build directories whose pathname contains spaces

[Julien Fischer]

Add a warning about build directories that contain spaces.

.INSTALL.in:
 	Mention that trying to build Mercury from a source tree
 	in a directory whose absolute pathname contains spaces
 	will not work.

Julien.

diff --git a/.INSTALL.in b/.INSTALL.in
index fae6571..51aad36 100755
--- a/.INSTALL.in
+++ b/.INSTALL.in
@@ -15,6 +15,10 @@
  #
  # Step 0.  Extract the files from the gzipped tar archive.
  #
+#      NOTE: do not extract the archive into a directory whose absolute
+#      pathname contains spaces as this will cause the installation to
+#      fail.
+#
  # Step 1.  Run `configure'.  (Just type `sh configure'.)
  #
  #          By default, the files will be installed in the directory