Index: sys/conf/kern.mk
===================================================================
--- sys/conf/kern.mk	(revision 218319)
+++ sys/conf/kern.mk	(working copy)
@@ -3,7 +3,7 @@
 #
 # Warning flags for compiling the kernel and components of the kernel.
 #
-# Note that the newly added -Wcast-qual is responsible for generating 
+# Note that the newly added -Wcast-qual is responsible for generating
 # most of the remaining warnings.  Warnings introduced with -Wall will
 # also pop up, but are easier to fix.
 .if ${CC:T:Micc} == "icc"
@@ -12,17 +12,18 @@
 .else
 CWARNFLAGS?=	-Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
 		-Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual \
-		-Wundef -Wno-pointer-sign -fformat-extensions
+		-Wundef -Wno-pointer-sign -fformat-extensions \
+		-Wmissing-include-dirs
 .endif
 #
 # The following flags are next up for working on:
-#	-W
+#	-Wextra
 
 #
 # On the i386, do not align the stack to 16-byte boundaries.  Otherwise GCC
 # 2.95 adds code to the entry and exit point of every function to align the
 # stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack
-# per function call.  While the 16-byte alignment may benefit micro benchmarks, 
+# per function call.  While the 16-byte alignment may benefit micro benchmarks,
 # it is probably an overall loss as it makes the code bigger (less efficient
 # use of code cache tag lines) and uses more stack (less efficient use of data
 # cache tag lines).  Explicitly prohibit the use of SSE and other SIMD