diff --git a/kmod/Makefile b/kmod/Makefile
index d0abca9b..54aafb03 100644
--- a/kmod/Makefile
+++ b/kmod/Makefile
@@ -1,38 +1,24 @@
 ALL: module
 
-#
-# SK_KSRC points to the kernel header build dir to build against.
-# On a running machine this could be /lib/modules/$(uname -r)/build with
-# the right kernel-headers package installed.  I tend to build on other
-# hosts so I extract the kernel-headers package for the target machine's
-# kernel in a dir somehere.
-#
-# sparse is critical for avoiding endian mistakes.  It should just work
-# if the sparse package is installed.
-#
-# but sometimes kernel-headers are broken.    For example, the
-# rhel 3.10.0-327.el7.x86_64 kernel needs the following patch.
-# We'll try to have a git tree with fixed headers.
-#
-#
-# diff --git a/include/linux/rh_kabi.h b/include/linux/rh_kabi.h
-# index 1767770..0a8e5f3 100644
-# --- a/include/linux/rh_kabi.h
-# +++ b/include/linux/rh_kabi.h
-# @@ -73,7 +73,6 @@
-#                 struct {                                \
-#                         _orig;                          \
-#                 } __UNIQUE_ID(rh_kabi_hide);            \
-# -               __RH_KABI_CHECK_SIZE_ALIGN(_orig, _new);        \
-#         }
-#
-#  #define _RH_KABI_REPLACE_UNSAFE(_orig, _new)   _new
+# default to building against the installed source for the running kernel
+ifeq ($(SK_KSRC),)
+SK_KSRC := $(shell echo /lib/modules/`uname -r`/build)
+endif
+
+# fail if sparse fails if we find it
+ifeq ($(shell sparse && echo found),found)
+SP =
+else
+SP = @:
+endif
+
+ARGS := CONFIG_SCOUTFS_FS=m -C $(SK_KSRC) M=$(CURDIR)/src
 
 all: module
 
 module:
-	make CONFIG_SCOUTFS_FS=m -C $(SK_KSRC) M=$(CURDIR)/src
-	make C=2 CF="-D__CHECK_ENDIAN__" CONFIG_SCOUTFS_FS=m -C $(SK_KSRC) M=$(CURDIR)/src
+	make $(ARGS)
+	$(SP) make C=2 CF="-D__CHECK_ENDIAN__" $(ARGS)
 
 clean:
-	make CONFIG_SCOUTFS_FS=m -C $(SK_KSRC) M=$(CURDIR)/src clean
+	make $(ARGS) clean