Require specific user action to compile without 64-bit support

The D-Bus type system isn't implementable without 64-bit support, although
for historical reasons we have some sort of semi-working support for
platforms with no 64-bit integers. Let's find out whether any
practically relevant platform still lacks these types...

(GLib appears to have required 64-bit integer types since 2001.)

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=35114
Reviewed-by: Lennart Poettering <lennart@poettering.net>

diff --git a/configure.ac b/configure.ac
index 03914e1..ced95e4 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -228,6 +228,12 @@ AC_CHECK_SIZEOF(void *)
 AC_CHECK_SIZEOF(long long)
 AC_CHECK_SIZEOF(__int64)
 
+AC_ARG_WITH([64-bit],
+  [AS_HELP_STRING([--without-64-bit],
+    [If you have to use this option, please report it as a bug])],
+  [],
+  [with_64_bit=yes])
+
 ### See what our 64 bit type is called
 AC_MSG_CHECKING([64-bit integer type])
 
@@ -265,13 +271,32 @@ $ac_cv_sizeof___int64)
   ;;
 esac
 
-if test -z "$dbusint64" ; then
+AS_IF(
+  [test "x$with_64_bit" = xno],
+  [
         DBUS_INT64_TYPE="no_int64_type_detected"
         DBUS_HAVE_INT64=0
         DBUS_INT64_CONSTANT=
         DBUS_UINT64_CONSTANT=
-        AC_MSG_RESULT([none found])
-else
+        AC_MSG_RESULT([disabled via --without-64-bit])
+  ],
+  dnl else if
+  [test -z "$dbusint64"],
+  [AC_MSG_RESULT([not found])
+  AC_MSG_ERROR([Could not find a 64-bit integer type.
+
+Please report a bug here with details of your platform and compiler:
+
+    http://bugs.freedesktop.org/enter_bug.cgi?product=DBus&component=core
+
+To compile D-Bus with all 64-bit integer types removed (not recommended), use
+the option "--without-64-bit".
+
+This option is likely to be removed in future, unless you report that your
+platform needs it.])
+  ],
+  dnl else
+  [
         DBUS_INT64_TYPE="$dbusint64"
         DBUS_HAVE_INT64=1
         DBUS_INT64_CONSTANT="$dbusint64_constant"
@@ -280,7 +305,7 @@ else
                AC_DEFINE_UNQUOTED(DBUS_INT64_PRINTF_MODIFIER, [$dbusint64_printf_modifier], [Define to printf modifier for 64 bit integer type])
        fi
         AC_MSG_RESULT($DBUS_INT64_TYPE)
-fi
+  ])
 
 AC_SUBST(DBUS_INT64_TYPE)
 AC_SUBST(DBUS_INT64_CONSTANT)
@@ -1745,3 +1770,16 @@ if test x$dbus_use_libxml = xtrue; then
         echo
        echo "WARNING: You have chosen to use libxml as your xml parser however this code path is not maintained by the D-Bus developers and if it breaks you get to keep the pieces.  If you have selected this option in err please reconfigure with expat (e.g. --with-xml=expat)."
 fi
+
+if test "x$DBUS_HAVE_INT64" = x0; then
+  AC_MSG_WARN([You have disabled 64-bit integers via --without-64-bit.
+
+  This removes parts of the standard D-Bus API and ABI (the 't' and 'x'
+  typecodes, the dbus_int64_t and dbus_uint64_t types, etc.) and should only be
+  used if your compiler lacks support for 64-bit integers. Please report a bug
+  with details of your platform and compiler.
+
+  This option is likely to be removed in future, unless the D-Bus developers
+  receive reports that it is still needed.
+  ])
+fi