dtc build failure on CentOS 7

[Joel Sherrill]

Hi

Looking in https://lists.rtems.org/pipermail/build/2021-November/030083.html,
I'm not sure what explains this error:

CC libfdt/fdt.o
libfdt/fdt.c: In function 'fdt_ro_probe_':
libfdt/fdt.c:27:11: error: 'FDT_ERR_ALIGNMENT' undeclared (first use
in this function)
   return -FDT_ERR_ALIGNMENT;
           ^
libfdt/fdt.c:27:11: note: each undeclared identifier is reported only
once for each function it appears in
libfdt/fdt.c: In function 'fdt_check_header':
libfdt/fdt.c:95:11: error: 'FDT_ERR_ALIGNMENT' undeclared (first use
in this function)
   return -FDT_ERR_ALIGNMENT;
           ^
make: *** [libfdt/fdt.o] Error 1