Makefile: fix cscope target

This target doesn't work with current directory layout. Just make cscope
index all .c and .h files.

While we're at it: add cscope output files to .gitignore.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

.gitignore

@@ -42,3 +42,11 @@ core
 /busybox.links
 /runtest-tempdir-links
 /testsuite/echo-ne
+
+#
+# cscope output
+#
+cscope.files
+cscope.in.out
+cscope.out
+cscope.po.out

Makefile

@@ -1165,24 +1165,7 @@ endif
 ALLSOURCE_ARCHS := $(ARCH)
 
 define all-sources
-	( find $(__srctree) $(RCS_FIND_IGNORE) \
-	       \( -name include -o -name arch \) -prune -o \
-	       -name '*.[chS]' -print; \
-	  for ARCH in $(ALLSOURCE_ARCHS) ; do \
-	       find $(__srctree)arch/$${ARCH} $(RCS_FIND_IGNORE) \
-	            -name '*.[chS]' -print; \
-	  done ; \
-	  find $(__srctree)security/selinux/include $(RCS_FIND_IGNORE) \
-	       -name '*.[chS]' -print; \
-	  find $(__srctree)include $(RCS_FIND_IGNORE) \
-	       \( -name config -o -name 'asm-*' \) -prune \
-	       -o -name '*.[chS]' -print; \
-	  for ARCH in $(ALLINCLUDE_ARCHS) ; do \
-	       find $(__srctree)include/asm-$${ARCH} $(RCS_FIND_IGNORE) \
-	            -name '*.[chS]' -print; \
-	  done ; \
-	  find $(__srctree)include/asm-generic $(RCS_FIND_IGNORE) \
-	       -name '*.[chS]' -print )
+	( find -regex '.*\.[ch]$$' )
 endef
 
 quiet_cmd_cscope-file = FILELST cscope.files