I'm beginning to think that this is an oversight in 10.1. Looking in /usr/doc/nail-11.20/INSTALL, in the section describing the Makefile variables, one finds
Code:
SENDMAIL Path to the de-facto standard /usr/lib/sendmail interface
normally offered by Unix MTAs. If only SMTP is used to send
mail, the value does not matter.
That is to say, if nail isn't compiled as "make SENDMAIL=/usr/sbin/sendmail", it would automatically look for Sendmail in /usr/lib/sendmail. The Slackbuild for Nail only has
Code:
make CFLAGS=-O2 PREFIX=/usr MANDIR=/usr/man MAILSPOOL=/var/spool/mail UCBINSTALL=/usr/bin/install
make install CFLAGS=-O2 PREFIX=/usr MANDIR=/usr/man MAILSPOOL=/var/spool/mail UCBINSTALL=/usr/bin/install DESTDIR=$PKG
No mention of SENDMAIL