FYI: fix --enable-gcc-warnings

[Akim Demaille]

Installed in master (in two patches because of a silly typo), and
in branch-2.5.

        * configure.ac: Use enable_gcc_warnings instead of enableval,
        which is valid only with AC_ARG_ENABLE.
(cherry picked from commit 1890a2a816dab86c23cc1d0af8fac3986335deb7)

Conflicts:

        configure.ac
---
 configure.ac |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/configure.ac b/configure.ac
index bdb2504..1fffa67 100644
--- a/configure.ac
+++ b/configure.ac
@@ -57,2 +57,2 @@ AC_PROG_CC_STDC
 # Gnulib (early checks).
 gl_EARLY

-AC_ARG_ENABLE(gcc-warnings,
+AC_ARG_ENABLE([gcc-warnings],
 [  --enable-gcc-warnings   turn on lots of GCC warnings (not recommended)],
-[case "${enableval}" in
+[case $enable_gcc_warnings in
    yes|no) ;;
-   *)      AC_MSG_ERROR([bad value ${enableval} for gcc-warnings option]) ;;
+   *)  AC_MSG_ERROR([invalid value for --gcc-warnings: $enable_gcc_warnings]);;
  esac],
-             [enableval=no])
-if test "${enableval}" = yes; then
+              [enable_gcc_warnings=no])
+if test "$enable_gcc_warnings" = yes; then
   gl_WARN_ADD([-Werror], [WERROR_CFLAGS])
   AC_SUBST([WERROR_CFLAGS])
   gl_WARN_ADD([-Wall])
--
1.7.7.4