[sed] command failure? Porting a project to FreeBSD

Hello

I am trying to bring these updated print drivers to FreeBSD:
https://github.com/utsushi/utsushi.git


There's the automake scripts in there that's sorta helpful but I seem to
have gotten stuck with something.

I made sure that my environmental variables are set
LDFLAGS -L/usr/local/lib
CPPFLAGS -I/usr/local/include

i run autoreconf -fmi
that does it's thing and everything goes smoothly

./configure also seems to run just fine

when I run make there's a problem; sed command just hangs, it's been there
for hours now and no change.

the line in the makefile looks like this:
$(srcdir)/utsushi/tag.hpp $(srcdir)/lib/tag.cpp: $(srcdir)/lib/tag.xml \
  $(srcdir)/lib/tag.xsl
format=`echo $_at_ | sed 's|.*\.\([^.]*\)$$|\1|'`; \
sed -n \
   -e "/^<!--/s/\.xml ::/.$$format --/" \
   -e '/^<!--/,/-->/{ /-->/d; s|^$$|//|p; s|^....|//|p; }' $< > $_at_; \
xsltproc --stringparam format $$format $(srcdir)/lib/tag.xsl $< >> $_at_
sed -i 's/SEC_N_("%1%")/"%1%"/' $_at_

I am not the best with sed but I feel like there might be some issues; I am
running tcsh shell, it could be it or that command is malformed.

Trying to run the same make file with gmake, I get this output.

format=`echo lib/tag.cpp | sed 's|.*\.\([^.]*\)$|\1|'`; \
sed -n \
    -e "/^<!--/s/\.xml ::/.$format --/" \
    -e '/^<!--/,/-->/{ /-->/d; s|^$|//|p; s|^....|//|p; }' lib/tag.xml >
lib/tag.cpp; \
xsltproc --stringparam format $format ./lib/tag.xsl lib/tag.xml >>
lib/tag.cpp
sed -i 's/SEC_N_("%1%")/"%1%"/' lib/tag.cpp
sed: 1: "lib/tag.cpp": extra characters at the end of l command
gmake: *** [Makefile:1042: lib/tag.cpp] Error 1

extra character at the end of | command. It's a bit unclear to me.

There's a tags.xml and tags.xsl in the ./lib/ directory so it seems to be a
sed issue.

Any assistance would be appreciated.

Best,
Owen