--- ghc-8.2.2/configure.ac~	2017-11-21 05:22:42.000000000 +0900
+++ ghc-8.2.2/configure.ac	2018-05-28 12:37:35.296728423 +0900
@@ -745,7 +745,7 @@
 AC_CACHE_CHECK([for version of sphinx-build], fp_cv_sphinx_version,
 changequote(, )dnl
 [if test -n "$SPHINXBUILD"; then
-  fp_cv_sphinx_version=`"$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/.* v\?\([0-9]\.[0-9]\.[0-9]\)/\1/' | head -n1`;
 fi;
 changequote([, ])dnl
 ])