cc -O2 -pipe  -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations search/twalk.c -o search/twalk -D_POSIX_C_SOURCE=202405L  -lm -lpthread 
search/twalk.c:11:19: error: unknown type name 'posix_tnode'
void (*foo)(const posix_tnode *, void (*)(const posix_tnode *, VISIT, int)) = twalk;
                  ^
search/twalk.c:11:49: error: unknown type name 'posix_tnode'
void (*foo)(const posix_tnode *, void (*)(const posix_tnode *, VISIT, int)) = twalk;
                                                ^
search/twalk.c:11:8: error: incompatible function pointer types initializing 'void (*)(const int *, void (*)(const int *, VISIT, int))' with an expression of type 'void (const void *, void (*)(const void *, VISIT, int))' [-Werror,-Wincompatible-function-pointer-types]
void (*foo)(const posix_tnode *, void (*)(const posix_tnode *, VISIT, int)) = twalk;
       ^                                                                      ~~~~~
3 errors generated.