Add a "COCCI" macro that we tell coccinelle is always defined.

This will let us give specific in-file equivalents to given macros
or preprocessor directives, to make things parse.

scripts/coccinelle/apply.sh

@@ -6,4 +6,4 @@
 top="$(dirname "$0")/../.."
 
 spatch -macro_file_builtins "$top"/scripts/coccinelle/tor-coccinelle.h \
-       -I "$top" -I "$top"/src -I "$top"/ext "$@"
+       -I "$top" -I "$top"/src -I "$top"/ext --defined COCCI "$@"

scripts/coccinelle/try_parse.sh

@@ -10,14 +10,16 @@ exitcode=0
 for fn in "$@"; do
 
     if spatch -macro_file_builtins "$top"/scripts/coccinelle/tor-coccinelle.h \
-              -I "$top" -I "$top"/src -I "$top"/ext --parse-c "$fn" \
+              -I "$top" -I "$top"/src -I "$top"/ext --defined COCCI \
+              --parse-c "$fn" \
               2>/dev/null | grep "perfect = 1" > /dev/null; then
         : # it's perfect
     else
         echo "$fn"
         if test "${VERBOSE}" != ""; then
             spatch -macro_file_builtins "$top"/scripts/coccinelle/tor-coccinelle.h \
-                   -I "$top" -I "$top"/src -I "$top"/ext --parse-c "$fn"
+                   -I "$top" -I "$top"/src -I "$top"/ext --defined COCCI \
+                   --parse-c "$fn"
         fi
         exitcode=1
     fi