It was a very indirect dependency, due to the way I compiled subversion (--with-berkeley-db). libsvn_fs-1.dll was in its turn dependent on libdb48.dll.
libdb48.dll wasn't in the zipfile. It now is:
https://phpdev.toolsforresearch.com/mod_svn_vc14_x64.zip I downloaded Apache 2.4.23 x64 from here (Apachehaus), added the svn so's plus the DLL's and added 5 lines to the httpd.conf:
LoadModule dav_module modules/mod_dav.so
LoadModule dav_fs_module modules/mod_dav_fs.so
LoadModule auth_digest_module modules/mod_auth_digest.so
LoadModule dav_svn_module modules/mod_dav_svn.so
LoadModule authz_svn_module modules/mod_authz_svn.so
bin\httpd -v
Server version: Apache/2.4.23 (Win64)
Server built: Jul 1 2016 10:38:22
bin\httpd -t -D DUMP_MODULES
Loaded Modules:
core_module (static)
win32_module (static)
mpm_winnt_module (static)
http_module (static)
so_module (static)
actions_module (shared)
alias_module (shared)
allowmethods_module (shared)
asis_module (shared)
auth_basic_module (shared)
authn_core_module (shared)
authn_file_module (shared)
authz_core_module (shared)
authz_groupfile_module (shared)
authz_host_module (shared)
authz_user_module (shared)
autoindex_module (shared)
cgi_module (shared)
dir_module (shared)
env_module (shared)
include_module (shared)
info_module (shared)
isapi_module (shared)
log_config_module (shared)
mime_module (shared)
negotiation_module (shared)
setenvif_module (shared)
socache_shmcb_module (shared)
ssl_module (shared)
status_module (shared)
dav_module (shared)
dav_fs_module (shared)
auth_digest_module (shared)
dav_svn_module (shared)
authz_svn_module (shared)