--- a/vmnet/Makefile
+++ b/vmnet/Makefile
@@ -43,7 +43,11 @@ INCLUDE      += -I$(SRCROOT)/shared
 endif
 
 
+ifdef KVERSION
+VM_UNAME = $(KVERSION)
+else
 VM_UNAME = $(shell uname -r)
+endif
 
 # Header directory for the running kernel
 ifdef LINUXINCLUDE
@@ -137,7 +137,7 @@
 endif
 
 # Add Spectre options when available
-CC_OPTS += $(call vm_check_gcc,-mindirect-branch=thunk -mindirect-branch-register,)
+CC_OPTS += $(call vm_check_gcc,-mindirect-branch-register,)
 
 include $(SRCROOT)/Makefile.kernel