List of the keywords of C, as ACL2 strings.
Definition:
(defconst *keywords* '("auto" "break" "case" "char" "const" "continue" "default" "do" "double" "else" "enum" "extern" "float" "for" "goto" "if" "inline" "int" "long" "register" "restrict" "return" "short" "signed" "sizeof" "static" "struct" "switch" "typedef" "union" "unsigned" "void" "volatile" "while" "_Alignas" "_Alignof" "_Atomic" "_Bool" "_Complex" "_Generic" "_Imaginary" "_Noreturn" "_Static_assert" "_Thread_local"))