PostGIS Error Building with `make` in ./extensions – Solution

I'm using code I checked out from SVN. Whenever I run make in ./extensions/, I get

 make
for DIR in postgis  postgis_tiger_geocoder  postgis_topology address_standardizer; do \
    echo "---- Making all in ${DIR}"; \
    make -C "${DIR}" all || exit 1; \
done
---- Making all in postgis
make[1]: Entering directory '/home/ecarroll/code/postgis/extensions/postgis'
mkdir -p sql_bits/
/usr/bin/perl -pe 's/BEGIN\;//g ; s/COMMIT\;//g' ../../postgis/postgis_for_extension.sql > sql_bits/postgis.sql
make -C ../../doc comments
make[2]: Entering directory '/home/ecarroll/code/postgis/doc'
make[2]: Nothing to be done for 'comments'.
make[2]: Leaving directory '/home/ecarroll/code/postgis/doc'
cp ../../doc/postgis_comments.sql sql_bits/postgis_comments.sql
cp: cannot stat '../../doc/postgis_comments.sql': No such file or directory
Makefile:72: recipe for target 'sql_bits/postgis_comments.sql' failed
make[1]: *** [sql_bits/postgis_comments.sql] Error 1
make[1]: Leaving directory '/home/ecarroll/code/postgis/extensions/postgis'
Makefile:26: recipe for target 'all' failed

Whenever I run make comments in the root I get a small portion of those errors,

make comments
make -C doc comments
make[1]: Entering directory '/home/ecarroll/code/postgis/doc'
make[1]: Nothing to be done for 'comments'.
make[1]: Leaving directory '/home/ecarroll/code/postgis/doc'

How do I resolve this?