[commit: ghc] master: configure.ac: Fix autotool warnings (798d2e2)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/798d2e2bc3d4bca4de0b62a2e4483138a2a46568/ghc

>---------------------------------------------------------------

commit 798d2e2bc3d4bca4de0b62a2e4483138a2a46568
Author: Erik de Castro Lopo <erikd at mega-nerd.com>
Date:   Sat Oct 24 11:53:06 2015 +0200

    configure.ac: Fix autotool warnings
    
    Test Plan: perl boot and check for warnings
    
    Reviewers: niteria, austin, bgamari
    
    Reviewed By: bgamari
    
    Subscribers: thomie
    
    Differential Revision: https://phabricator.haskell.org/D1364


>---------------------------------------------------------------

798d2e2bc3d4bca4de0b62a2e4483138a2a46568
 configure.ac | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/configure.ac b/configure.ac
index dabcbcd..2f1656d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -772,15 +772,15 @@ fi
 
 dnl ** check for Sphinx toolchain
 AC_PATH_PROG(SPHINXBUILD,sphinx-build)
-AC_CACHE_CHECK([for version of sphinx-build], sphinx_version,
+AC_CACHE_CHECK([for version of sphinx-build], fp_cv_sphinx_version,
 changequote(, )dnl
 [if test -n "$SPHINXBUILD"; then
-  sphinx_version=`"$SPHINXBUILD" --version 2>&1 | sed 's/Sphinx\( (sphinx-build)\)\? v\?\([0-9]\.[0-9]\.[0-9]\)/\2/' | head -n1`;
+  fp_cv_sphinx_version=`"$SPHINXBUILD" --version 2>&1 | sed 's/Sphinx\( (sphinx-build)\)\? v\?\([0-9]\.[0-9]\.[0-9]\)/\2/' | head -n1`;
 fi;
 changequote([, ])dnl
 ])
-FP_COMPARE_VERSIONS([$sphinx_version],-lt,1.0.0,
-    [AC_MSG_ERROR([Sphinx version 1.0.0 or later is required to build documentation]); SPHINXBUILD=;])
+FP_COMPARE_VERSIONS([$fp_cv_sphinx_version],-lt,1.0.0,
+    [AC_MSG_WARN([Sphinx version 1.0.0 or later is required to build documentation]); SPHINXBUILD=;])
 
 dnl ** check for xelatex
 AC_PATH_PROG(XELATEX,xelatex)