compile error master SSL_R_VERSION_TOO_HIGH:

Hello,

On "Debian GNU/Linux 9 (stretch)", compiling master just now, I get the
following (interspersed with some output fom my build script):

-- [2020.06.27 19:07:42 HEAD/1] ./configure
--prefix=/home/aardvark/pg_stuff/pg_installations/pgsql.HEAD
--bindir=/home/aardvark/pg_stuff/pg_installations/pgsql.HEAD/bin.fast
--l
ibdir=/home/aardvark/pg_stuff/pg_installations/pgsql.HEAD/lib.fast
--with-pgport=6514 --quiet --enable-depend --with-openssl --with-perl
--with-libxml --with-libxslt --with-zlib
--enable-tap-tests --with-extra-version=_0627_b63d

-- [2020.06.27 19:08:06 HEAD/1] make core: make --quiet -j 4
be-secure-openssl.c: In function ‘be_tls_open_server’:
be-secure-openssl.c:477:11: error: ‘SSL_R_VERSION_TOO_HIGH’ undeclared
(first use in this function)
477 | case SSL_R_VERSION_TOO_HIGH:
| ^~~~~~~~~~~~~~~~~~~~~~
be-secure-openssl.c:477:11: note: each undeclared identifier is reported
only once for each function it appears in
be-secure-openssl.c:478:11: error: ‘SSL_R_VERSION_TOO_LOW’ undeclared
(first use in this function); did you mean ‘SSL_R_MESSAGE_TOO_LONG’?
478 | case SSL_R_VERSION_TOO_LOW:
| ^~~~~~~~~~~~~~~~~~~~~
| SSL_R_MESSAGE_TOO_LONG
make[3]: *** [be-secure-openssl.o] Error 1
make[2]: *** [libpq-recursive] Error 2
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [all-backend-recurse] Error 2
make: *** [all-src-recurse] Error 2
../../../src/Makefile.global:919: recipe for target
'be-secure-openssl.o' failed
common.mk:39: recipe for target 'libpq-recursive' failed
Makefile:42: recipe for target 'all-backend-recurse' failed
GNUmakefile:11: recipe for target 'all-src-recurse' failed

To be honest I have no idea what needs to be fixed...

Thanks,

Erik Rijkers