Tweak cppcheck to test with better settings

c99 is probably a better standard to check against.
Also try to cut down on ASN.1 template and config file testing,
since these fail anyway, not being full source files yet.

Change-Id: I289c35498cf9eba757e46601b4610f085ec4ba77
Signed-off-by: Jaap Keuter <jaap.keuter@xs4all.nl>
Reviewed-on: https://code.wireshark.org/review/28019
Reviewed-by: Anders Broman <a.broman58@gmail.com>

tools/cppcheck/cppcheck.sh

@@ -80,9 +80,9 @@ fi
 # runs and we aren't left with broken HTML.
 trap : INT
 
-$CPPCHECK --force --enable=style $QUIET  \
-          $SUPPRESSIONS $INCLUDES        \
-          --std=c89 --template=$TEMPLATE \
+$CPPCHECK --force --enable=style $QUIET    \
+          $SUPPRESSIONS $INCLUDES -i asn1/ \
+          --std=c99 --template=$TEMPLATE   \
           -j $THREADS $TARGET 2>&1 | colorize
 
 if [ "$MODE" = "html" ]; then