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