1 files changed, 6 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 0738648..b22cb0d 100644
--- a/Makefile
+++ b/Makefile
@@ -238,6 +238,12 @@ $(info (!!) Edit the file .config to override the default configuration.)
 $(error Cannot build without access to the LITMUS^RT kernel source)
 endif
 
+kernel-unistd-hdrs := $(foreach file,${unistd-headers},${LITMUS_KERNEL}/$(file))
+hdr-ok     := $(shell grep '\#include "litmus/unistd' ${kernel-unistd-hdrs} )
+ifeq ($(strip $(hdr-ok)),)
+$(error Your kernel headers do not seem to be LITMUS^RT headers)
+endif
+
 config-ok  := $(shell test -f "${LITMUS_KERNEL}/${word 1,${unistd-headers}}" \
         || echo fail )
 ifneq ($(config-ok),)