Custom kernel with PIPEX without IPSEC failed to compile

[Ivan Solonin]

I tried to compile custom kernel in the 5.5 release of OpenBSD on landisk 
platform with PIPEX, but found requirment of IPSEC by PIPEX.
As I've found in file /sys/netinet/udp_usrreq.c it uses IPSEC only with L2TP to 
distinguish IPsec packets against non-IPsec.
Is PIPEX so strong require IPSEC?
Is it possible to compile custom kernel with PIPEX enabled, but without IPSEC?