nmk: add cscope, etags and ctags wrappers

Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

scripts/nmk/scripts/tools.mk

@@ -21,9 +21,12 @@ FIND		:= find
 SH		:= $(shell if [ -x "$$BASH" ]; then echo $$BASH;        \
                         else if [ -x /bin/bash ]; then echo /bin/bash;  \
                         else echo sh; fi ; fi)
+CSCOPE		:= cscope
+ETAGS		:= etags
+CTAGS		:= ctags
 
 export RM LD CC CPP AS AR STRIP OBJCOPY OBJDUMP
-export NM SH MAKE MKDIR AWK PERL PYTHON SH
+export NM SH MAKE MKDIR AWK PERL PYTHON SH CSCOPE
 
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