configure: don't support asm without memalign

I tried it, and it broke horribly. We should definitively rule out this.

Unfortunately, it's not as easy as just setting `disable asm` here, because
asm having been enabled will already have affected the build process further
upstream - conversely, we don't know whether or not memalign exists until
fairly late in the build process, and I'm not about to go destroying
the current organization of the file just to work around this.

So an error message it is.

configure

@@ -8183,6 +8183,13 @@ haiku)
     ;;
 esac
 
+if ! enabled_any memalign posix_memalign aligned_malloc; then
+    if enabled_any asm inline_asm; then
+        die "ERROR: Building with assembly enabled is not supported on platforms "\
+            "without aligned memory allocations! Try reconfiguring with --disable-asm"
+    fi
+fi
+
 flatten_extralibs(){
     nested_entries=
     list_name=$1