[c++tools] Fix typo and weird syntax in configure script

[Eric Botcazou]

Tested on x86-64/Linux, applied on mainline and 11 branch as obvious.


2021-05-25  Eric Botcazou  <ebotca...@adacore.com>

c++tools/
        * configure.ac (--enable-maintainer-mode): Fix typo and weird syntax.
        * configure: Regenerate.

-- 
Eric Botcazou
diff --git a/c++tools/configure.ac b/c++tools/configure.ac
index 5771f2ace68..c8f85209188 100644
--- a/c++tools/configure.ac
+++ b/c++tools/configure.ac
@@ -58,9 +58,9 @@ AS_HELP_STRING([--enable-maintainer-mode],
 [enable maintainer mode.  Add rules to rebuild configurey bits]),,
 [enable_maintainer_mode=no])
 case "$enable_maintainer_mode" in
-  ("yes") maintainer_mode=yes ;;
-  ("no") maintainer=no ;;
-  (*) AC_MSG_ERROR([unknown maintainer mode $enable_maintainer_mode]) ;;
+  yes) maintainer_mode=yes ;;
+  no) maintainer_mode=no ;;
+  *) AC_MSG_ERROR([unknown maintainer mode $enable_maintainer_mode]) ;;
 esac
 AC_MSG_CHECKING([maintainer-mode])
 AC_MSG_RESULT([$maintainer_mode])