[PATCH V2] scripts: coccicheck: Do not use shift command when rule is specfified

[Sumera Priyadarsini <sylphrenadin@gmail.com>]

The command "make coccicheck C=1 CHECK=scripts/coccicheck" results in the
error:
	./scripts/coccicheck: line 65: -1: shift count out of range

This happens because every time the C variable is specified,
the shell arguments need to be "shifted" in order to take only
the last argument, which is the C file to test. These shell arguments
mostly comprise flags that have been set in the Makefile. However,
when coccicheck is specified in the make command as a rule, the
number of shell arguments is zero, thus passing the invalid value -1
to the shift command, resulting in an error.

Modify coccicheck to use the shift command only when
number of shell arguments is not zero.

Signed-off-by: Sumera Priyadarsini <sylphrenadin@gmail.com>

---
Changes in V2:
	- Fix spelling errors as suggested by Markus Elfring
---
 scripts/coccicheck | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/scripts/coccicheck b/scripts/coccicheck
index e04d328210ac..5c8df337e1e3 100755
--- a/scripts/coccicheck
+++ b/scripts/coccicheck
@@ -61,9 +61,19 @@ COCCIINCLUDE=${COCCIINCLUDE// -include/ --include}
 if [ "$C" = "1" -o "$C" = "2" ]; then
     ONLINE=1
 
-    # Take only the last argument, which is the C file to test
-    shift $(( $# - 1 ))
-    OPTIONS="$COCCIINCLUDE $1"
+    # If the rule coccicheck is specified when calling make, number of
+    # arguments is zero
+    if [ $# -ne 0 ]; then
+	    # Take only the last argument, which is the C file to test
+	    shift $(( $# -1 ))
+	    OPTIONS="$COCCIINCLUDE $1"
+    else
+	if [ "$KBUILD_EXTMOD" = "" ] ; then
+		OPTIONS="--dir $srctree $COCCIINCLUDE"
+	else
+		OPTIONS="--dir $KBUILD_EXTMOD $COCCIINCLUDE"
+	fi
+    fi
 
     # No need to parallelize Coccinelle since this mode takes one input file.
     NPROC=1
-- 
2.25.1