Make check-names.sh find the right names in 3rdparty

Essentially adds the Everest .h and .c files to the various variables. This
should be generalized at some point, but there is no infrastructure for this
yet.
diff --git a/tests/scripts/list-macros.sh b/tests/scripts/list-macros.sh
index 3fa66f1..9a89737 100755
--- a/tests/scripts/list-macros.sh
+++ b/tests/scripts/list-macros.sh
@@ -8,6 +8,7 @@
 fi
 
 HEADERS=$( ls include/mbedtls/*.h include/psa/*.h | egrep -v 'compat-1\.3\.h' )
+HEADERS="$HEADERS 3rdparty/everest/include/everest/everest.h 3rdparty/everest/include/everest/x25519.h"
 
 # White-list macros we want to be able to refer to that don't exist in the
 # crypto library, useful when referring to macros in Mbed TLS from comments.