clang -O2  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations ftw/S_TYPEISSHM.c -o ftw/S_TYPEISSHM -D_POSIX_C_SOURCE=202405L  -lm  -lintl
ftw/S_TYPEISSHM.c:9:2: error: "S_TYPEISSHM is not defined"
#error "S_TYPEISSHM is not defined"
 ^
1 error generated.