=> Bootstrap dependency digest>=20010302: found digest-20121220
=> Checksum SHA1 OK for rcs-5.9.2.tar.xz
=> Checksum RMD160 OK for rcs-5.9.2.tar.xz
===> Installing dependencies for rcs-5.9.2
=> Tool dependency gmake>=3.81: found gmake-4.0
===> Overriding tools for rcs-5.9.2
===> Extracting for rcs-5.9.2
===> Patching for rcs-5.9.2
===> Creating toolchain wrappers for rcs-5.9.2
===> Configuring for rcs-5.9.2
=> Modifying GNU configure scripts to avoid --recheck
=> Replacing config-guess with pkgsrc versions
=> Replacing config-sub with pkgsrc versions
=> Replacing install-sh with pkgsrc version
=> Replacing sh interpreter in build-aux/extract-help.
checking for a BSD-compatible install... /usr/bin/install -c -o root -g operator
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... build-aux/install-sh -c -d
checking for gawk... /usr/bin/awk
checking whether make sets $(MAKE)... yes
checking whether make supports nested variables... yes
checking if /usr/bin/diff works like GNU diff... yes
checking for /usr/bin/diff... /usr/bin/diff
checking diff success status... 0
checking diff failure status... 1
checking diff trouble status... 2
checking diff options for RCS... -an
checking if diff understands --label... yes
checking for gdiff3... no
checking for diff3... no
configure: error: Could not find a diff3 program (tried: gdiff3 diff3)
*** Error code 1

Stop.
bmake: stopped in /usr/pkgsrc/devel/rcs
*** Error code 1

Stop.
bmake: stopped in /usr/pkgsrc/devel/rcs