Error during make, second install

Hey,

I installed PostgreSQL source for the first time a few weeks ago. I am now
just getting to my first pull-and-reinstall. I run make again at the top
of the repo and I get:

git @ 7fe3083f4

gcc -Wall -Wmissing-prototypes -Wpointer-arith
-Wdeclaration-after-statement -Werror=vla -Wendif-labels
-Wmissing-format-attribute -Wimplicit-fallthrough=3 -Wformat-security
-fno-strict-aliasing -fwrapv -fexcess-precision=standard
-Wno-format-truncation -O2 [...] -L../../src/port -L../../src/common
-Wl,--as-needed -Wl,-rpath,'/usr/local/pgsql/lib',--enable-new-dtags
-Wl,-E -lpthread -lrt -ldl -lm -o postgres
catalog/catalog.o: In function `GetNewRelFileNode':
catalog.c:(.text+0x3f3): undefined reference to `ParallelMasterBackendId'
catalog/storage.o: In function `RelationCreateStorage':
storage.c:(.text+0x283): undefined reference to `ParallelMasterBackendId'
utils/adt/dbsize.o: In function `pg_relation_filepath':
dbsize.c:(.text+0x166e): undefined reference to `ParallelMasterBackendId'
collect2: error: ld returned 1 exit status
Makefile:66: recipe for target 'postgres' failed
make[2]: *** [postgres] Error 1
make[2]: Leaving directory '/home/postgres/postgresql/src/backend'
Makefile:42: recipe for target 'all-backend-recurse' failed
make[1]: *** [all-backend-recurse] Error 2
make[1]: Leaving directory '/home/postgres/postgresql/src'
GNUmakefile:11: recipe for target 'all-src-recurse' failed
make: *** [all-src-recurse] Error 2

I then ran ./configure again and got the same result. Ubuntu 18.04.

Simply checking out and re-making 3a990a12635 (plus my two patches) works
just fine.

Please advise, fixing stuff in the C parts of the codebase is not a skill
I've picked up yet - been focused on docs and tests.

Thanks!

David J.