Tricked by gnats@ again... Okay, what happens when you try only this diff:
Index: dsdt.c
===================================================================
RCS file: /cvs/src/sys/dev/acpi/dsdt.c,v
retrieving revision 1.185
diff -u -p -r1.185 dsdt.c
--- dsdt.c 22 Apr 2011 18:22:01 -0000 1.185
+++ dsdt.c 26 May 2011 13:33:58 -0000
@@ -1484,7 +1484,6 @@ char *aml_valid_osi[] = {
"Windows 2001 SP3",
"Windows 2001 SP4",
"Windows 2006",
- "Windows 2009",
NULL
};
