configure: Fix FAST_CMOV detection on AMD64

The code that enabled FAST_CMOV by default was only executed in the
32-bit case. As a result FAST_CMOV was never automatically enabled on
AMD64. Fix this by moving the code out of the arch-specific section so
it's executed on both x86 and AMD64; it's harmless on architectures
that do not support CMOV.

configure

@@ -1870,12 +1870,6 @@ EOF
       esac
     fi
 
-    if test $_cmov = "yes" && test $_fast_cmov = "auto" ; then
-        _fast_cmov="yes"
-    else
-        _fast_cmov="no"
-    fi
-
     echores "$proc"
     ;;
 
@@ -2223,6 +2217,12 @@ EOF
     ;;
 esac # case "$host_arch" in
 
+if test $_cmov = "yes" && test $_fast_cmov = "auto" ; then
+    _fast_cmov="yes"
+else
+    _fast_cmov="no"
+fi
+
 if test "$_runtime_cpudetection" = yes ; then
   if x86 ; then
     test "$_cmov"     != no && _cmov=yes