AX_SUBMODULE: drop options that are meaningless given possible choices

diff --git a/doc/user.pod b/doc/user.pod
index 30be3a0..480f3df 100644 (file)
--- a/doc/user.pod
+++ b/doc/user.pod
@@ -109,10 +109,6 @@ and either C<PolyLib> or C<piplib>.
 
 Installation prefix for C<isl>
 
-=item C<--with-gmp>
-
-Dummy option, included for consistency.  Always set to C<system>.
-
 =item C<--with-gmp-prefix>
 
 Installation prefix for C<GMP> (architecture-independent files).

diff --git a/m4/ax_submodule.m4 b/m4/ax_submodule.m4
index 272fa59..17e357f 100644 (file)
--- a/m4/ax_submodule.m4
+++ b/m4/ax_submodule.m4
@@ -1,9 +1,10 @@
 AC_DEFUN([AX_SUBMODULE],
 [
 
-AC_ARG_WITH($1,
-       [AS_HELP_STRING([--with-$1=$2],
-                       [Which $1 to use [default=$3]])])
+m4_if(m4_bregexp($2,|,choice),choice,
+       [AC_ARG_WITH($1,
+               [AS_HELP_STRING([--with-$1=$2],
+                               [Which $1 to use [default=$3]])])])
 case "system" in
 $2)
        AC_ARG_WITH($1_prefix,
@@ -13,12 +14,10 @@ $2)
                    [AS_HELP_STRING([--with-$1-exec-prefix=DIR],
                                    [Exec prefix of $1 installation])])
 esac
-case "build" in
-$2)
-       AC_ARG_WITH($1_builddir,
-                   [AS_HELP_STRING([--with-$1-builddir=DIR],
-                                   [Location of $1 builddir])])
-esac
+m4_if(m4_bregexp($2,build,build),build,
+       [AC_ARG_WITH($1_builddir,
+               [AS_HELP_STRING([--with-$1-builddir=DIR],
+                               [Location of $1 builddir])])])
 if test "x$with_$1_prefix" != "x" -a "x$with_$1_exec_prefix" = "x"; then
        with_$1_exec_prefix=$with_$1_prefix
 fi