Build Wine as 32-bit by default on x86-64, and added a --enable-win64
option for people who want to play with 64-bit support.

diff --git a/configure b/configure
index 8bf1dec..2bb7b49 100755
--- a/configure
+++ b/configure
@@ -863,6 +863,8 @@
   --disable-win16         do not include Win16 support
   --disable-debug         compile out all debugging messages
   --disable-trace         compile out TRACE messages
+  --enable-win64          build a Win64 emulator on AMD64 (won't run Win32
+                          binaries)
 
 Optional Packages:
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
@@ -1377,6 +1379,11 @@
   enableval="$enable_trace"
 
 fi;
+# Check whether --enable-win64 or --disable-win64 was given.
+if test "${enable_win64+set}" = set; then
+  enableval="$enable_win64"
+
+fi;
 
 
 # Check whether --with-opengl or --without-opengl was given.
@@ -1478,6 +1485,17 @@
 host_os=`echo $ac_cv_host | sed 's/^\([^-]*\)-\([^-]*\)-\(.*\)$/\3/'`
 
 
+case $host in
+  x86_64*linux*)
+    if test "x$enable_win64" != "xyes"
+    then
+      test -n "$CC" || CC="gcc -m32"
+      test -n "$LD" || LD="ld -m elf_i386"
+      test -n "$AS" || AS="as --32"
+    fi
+    ;;
+esac
+
 echo "$as_me:$LINENO: checking whether ${MAKE-make} sets \$(MAKE)" >&5
 echo $ECHO_N "checking whether ${MAKE-make} sets \$(MAKE)... $ECHO_C" >&6
 set dummy ${MAKE-make}; ac_make=`echo "$2" | sed 'y,:./+-,___p_,'`