Build error on FreeBSD 12.2

[takelley1]

Using HEAD on branch v5.3
Here's the output from running ./configure on FreeBSD 12.2:

checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... ./install-sh -c -d
checking for gawk... no
checking for mawk... no
checking for nawk... nawk
checking whether make sets $(MAKE)... yes
checking whether make supports nested variables... yes
checking for g++... g++
checking whether the C++ compiler works... yes
checking for C++ compiler default output file name... a.out
checking for suffix of executables...
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C++ compiler... yes
checking whether g++ accepts -g... yes
checking whether make supports the include directive... yes (GNU style)
checking dependency style of g++... gcc3
checking dependency style of g++... (cached) gcc3
checking for gcc... gcc
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking whether gcc understands -c and -o together... yes
checking dependency style of gcc... gcc3
checking dependency style of gcc... (cached) gcc3
checking how to run the C preprocessor... gcc -E
checking whether ln -s works... yes
checking whether make sets $(MAKE)... (cached) yes
checking how to run the C++ preprocessor... g++ -E
checking for grep that handles long lines and -e... /usr/bin/grep
checking for egrep... /usr/bin/grep -E
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking arpa/inet.h usability... yes
checking arpa/inet.h presence... yes
checking for arpa/inet.h... yes
checking fcntl.h usability... yes
checking fcntl.h presence... yes
checking for fcntl.h... yes
checking limits.h usability... yes
checking limits.h presence... yes
checking for limits.h... yes
checking netdb.h usability... yes
checking netdb.h presence... yes
checking for netdb.h... yes
checking netinet/in.h usability... yes
checking netinet/in.h presence... yes
checking for netinet/in.h... yes
checking for stdlib.h... (cached) yes
checking for string.h... (cached) yes
checking sys/socket.h usability... yes
checking sys/socket.h presence... yes
checking for sys/socket.h... yes
checking sys/time.h usability... yes
checking sys/time.h presence... yes
checking for sys/time.h... yes
checking syslog.h usability... yes
checking syslog.h presence... yes
checking for syslog.h... yes
checking for unistd.h... (cached) yes
checking locale.h usability... yes
checking locale.h presence... yes
checking for locale.h... yes
checking for sys/types.h... (cached) yes
checking sys/un.h usability... yes
checking sys/un.h presence... yes
checking for sys/un.h... yes
checking sys/poll.h usability... yes
checking sys/poll.h presence... yes
checking for sys/poll.h... yes
checking sys/epoll.h usability... no
checking sys/epoll.h presence... no
checking for sys/epoll.h... no
checking sys/resource.h usability... yes
checking sys/resource.h presence... yes
checking for sys/resource.h... yes
checking pwd.h usability... yes
checking pwd.h presence... yes
checking for pwd.h... yes
checking grp.h usability... yes
checking grp.h presence... yes
checking for grp.h... yes
checking byteswap.h usability... no
checking byteswap.h presence... no
checking for byteswap.h... no
checking whether byte ordering is bigendian... no
checking if zlib should be statically linked... no
checking for zlib... checking zlib.h usability... yes
checking zlib.h presence... yes
checking for zlib.h... yes
checking for gzdopen in -lz... yes
yes
checking for pid_t... yes
checking for size_t... yes
checking for off_t... yes
checking for uid_t in sys/types.h... yes
checking vfork.h usability... no
checking vfork.h presence... no
checking for vfork.h... no
checking for fork... yes
checking for vfork... yes
checking for working fork... yes
checking for working vfork... (cached) yes
checking for dup2... yes
checking for gettimeofday... yes
checking for memset... yes
checking for select... yes
checking for strerror... yes
checking for strstr... yes
checking for strtol... yes
checking for setuid... yes
checking for setgid... yes
checking for umask... yes
checking for seteuid... yes
checking for setreuid... yes
checking for setlocale... yes
checking for library containing floor... none required
checking for library containing gethostbyname... none required
checking for library containing socket... none required
checking for library containing inet_aton... none required
checking for backside with both hands... no
checking build os... checking build system type... amd64-unknown-freebsd12.2
freebsd12.2
checking for debug option... no
checking for newdebug option... yes
checking for netdebug option... no
checking for REdebug option... no
checking for proxy user... no
checking for proxy group... no
checking for piddir... no
checking for logdir... no
./configure: PKG_PROG_PKG_CONFIG: not found
checking for PCRE support... yes
./configure: 6948: Syntax error: word unexpected (expecting ")")

If I remove line 6948 in configure, I get the following output (the beginning is the same as above):

./configure: PKG_PROG_PKG_CONFIG: not found
checking for PCRE support... yes
checking pthread.h usability... yes
checking pthread.h presence... yes
checking for pthread.h... yes
Version: 10.2.0
checking for large file support... getconf: no such configuration parameter `LFS_CFLAGS'
getconf: no such configuration parameter `LFS_LDFLAGS'
getconf: no such configuration parameter `LFS_LIBS'
yes
checking for original destination IP checking support... no
checking for type collision with off_t... yes
checking for clamd support... no
checking for avastd support... no
checking for icap support... no
checking for kavd support... no
checking for command-line content scanner support... no
checking for NTLM support... no
checking for SSL MITM support... ./configure: 7645: Syntax error: word unexpected (expecting
")")

Finally, if I remove line 7645 in configure, the script completes successfully.