compilation fails on 1-core VM

Describe the bug When building the frr-7.3.1 as packaged in our openSUSE Linux distribution, the build fails on 1-core VMs but succeeds on 4-core VMs. This is indicative of insuffiently specified build dependencies.

[x] Did you check if this is a duplicate issue? [x] Did you test it on the latest FRRouting/frr master branch?

To Reproduce Steps to reproduce the behavior (on openSUSE or Debian):

osc checkout openSUSE:Factory/frr && cd $_
osc build --vm-type=kvm -j1 --noservice
See error

Expected behavior Build should not fail

Screenshots Build log has

 gcc -std=gnu11 -DHAVE_CONFIG_H -DSYSCONFDIR=\"/etc/frr/\" -DCONFDATE=0 -I.  -I. -I./include -I./lib -I. -I./include -I./lib          -ffat-lto-objects -fno-omit-frame-pointer -funwind-tables -Wall -Wextra -Wmissing-prototypes -Wmissing-declarations -Wpointer-arith -Wbad-function-cast -Wwrite-strings -Wno-unused-result -Wno-unused-parameter -Wno-missing-field-initializers -pthread -c -o zebra/zebra_mlag.o zebra/zebra_mlag.c
 In file included from zebra/zebra_mlag.c:29:
 ./zebra/zebra_mlag.h:30:10: fatal error: mlag/mlag.pb-c.h: No such file or directory
    30 | #include "mlag/mlag.pb-c.h"
       |          ^~~~~~~~~~~~~~~~~~
 compilation terminated.
 make[1]: *** [Makefile:7578: zebra/zebra_mlag.o] Error 1 
 make[1]: Leaving directory '/home/abuild/rpmbuild/BUILD/frr-frr-7.3.1'
 make: *** [Makefile:4506: all] Error 2

Versions

FRR Version 7.3.1 and master

Additional context This issue was found as part of my work on reproducible builds for openSUSE.

FRRouting / frr

compilation fails on 1-core VM #6576