Aarch64 build fails with missing files

I’m having trouble building from source on an aarch64 platform running CentOS 7. The configure file and subsequent Makefile get generated OK.
However the build step (with make or make dist ) fails due to missing src/resmom/mom_mach.c and mom_mach.h in either src/include or src/resmom/ .

I was following the instructions here https://pbspro.atlassian.net/wiki/spaces/PBSPro/pages/13991940/Building+PBS+Pro+Using+rpmbuild

Any idea why these files can’t be found or are being searched for if they should be? The don’t seem to be in the source tree.