configure: detect sparc64 automatically

Signed-off-by: Mans Rullgard <mans@mansr.com>

configure

@@ -2474,9 +2474,8 @@ case "$arch" in
     sh4|sh)
         arch="sh4"
     ;;
-    sun4u|sparc64)
+    sun4u|sparc*)
         arch="sparc"
-        subarch="sparc64"
     ;;
     tilegx|tile-gx)
         arch="tilegx"
@@ -2671,7 +2670,7 @@ check_64bit(){
 }
 
 case "$arch" in
-    alpha|ia64|sparc)
+    alpha|ia64)
         spic=$shared
     ;;
     mips)
@@ -2685,6 +2684,10 @@ case "$arch" in
     ppc)
         check_64bit ppc ppc64 'sizeof(void *) > 4'
     ;;
+    sparc)
+        check_64bit sparc sparc64 'sizeof(void *) > 4'
+        spic=$shared
+    ;;
     x86)
         check_64bit x86_32 x86_64 'sizeof(void *) > 4'
         if test "$subarch" = "x86_64"; then