fix out-of-tree installing

The current install rules assume that we are installing out of the source
dir, but this fails when building out-of-tree.  Tweak the install rule so
it works regardless.

BUG=chromium-os:33327
TEST=`emerge-x86-alex libevdev` still works

Change-Id: I4197b89dabfe2aa67dd2f6f85927e56c94a69404
Reviewed-on: https://gerrit.chromium.org/gerrit/29629
Reviewed-by: Dennis Kempin <denniskempin@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Chung-yih Wang <cywang@chromium.org>
Commit-Ready: Mike Frysinger <vapier@chromium.org>
diff --git a/include/module.mk b/include/module.mk
index 9b7dedf..b3415cd 100755
--- a/include/module.mk
+++ b/include/module.mk
@@ -5,11 +5,8 @@
 include common.mk
 
 install-header: CC_LIBRARY(src/libevdev.so.0)
-	install -D -m 0644 include/libevdev/libevdev.h \
-		 $(DESTDIR)/usr/include/libevdev/libevdev.h
-	install -D -m 0664 include/libevdev/libevdev_event.h \
-		 $(DESTDIR)/usr/include/libevdev/libevdev_event.h
-	install -D -m 0664 include/libevdev/libevdev_mt.h \
-		 $(DESTDIR)/usr/include/libevdev/libevdev_mt.h
-	install -D -m 0664 include/libevdev/libevdev_log.h \
-		 $(DESTDIR)/usr/include/libevdev/libevdev_log.h
\ No newline at end of file
+	set -e; \
+	for h in libevdev.h libevdev_event.h libevdev_mt.h libevdev_log.h; do \
+		install -D -m 0644 $(SRC)/include/libevdev/$$h \
+			$(DESTDIR)/usr/include/libevdev/$$h; \
+	done