Error generated by `./configure` with PHP 7.1.5 on OS X 10.12.5

configure.stdout

 > './configure'  '--prefix=/usr/local/Cellar/php56/5.6.24' '--localstatedir=/usr/local/var' '--sysconfdir=/usr/local/etc/php/5.6' '--with-config-file-path=/usr/local/etc/php/5.6' '--with-config-file-scan-dir=/usr/local/etc/php/5.6/conf.d' '--mandir=/usr/local/Cellar/php56/5.6.24/share/man' '--enable-bcmath' '--enable-calendar' '--enable-dba' '--enable-exif' '--enable-ftp' '--enable-gd-native-ttf' '--enable-mbregex' '--enable-mbstring' '--enable-shmop' '--enable-soap' '--enable-sockets' '--enable-sysvmsg' '--enable-sysvsem' '--enable-sysvshm' '--enable-wddx' '--enable-zip' '--with-freetype-dir=/usr/local/opt/freetype' '--with-gd' '--with-gettext=/usr/local/opt/gettext' '--with-iconv-dir=/usr' '--with-icu-dir=/usr/local/opt/icu4c' '--with-jpeg-dir=/usr/local/opt/jpeg' '--with-kerberos=/usr' '--with-libedit' '--with-mhash' '--with-ndbm=/usr' '--with-png-dir=/usr/local/opt/libpng' '--with-xmlrpc' '--with-zlib=/usr' '--with-readline=/usr/local/opt/readline' '--without-gmp' '--without-snmp' '--with-libxml-dir=/usr/local/opt/libxml2' '--with-pdo-odbc=unixODBC,/usr/local/opt/unixodbc' '--with-unixODBC=/usr/local/opt/unixodbc' '--with-apxs2=/usr/sbin/apxs' '--libexecdir=/usr/local/Cellar/php56/5.6.24/libexec' '--with-bz2=/usr' '--disable-debug' '--with-openssl=/usr/local/opt/openssl' '--enable-fpm' '--with-fpm-user=_www' '--with-fpm-group=_www' '--with-curl' '--with-xsl=/usr' '--with-mysql-sock=/tmp/mysql.sock' '--with-mysqli=mysqlnd' '--with-pdo-mysql=mysqlnd' '--disable-opcache' '--enable-pcntl' '--without-pear' '--enable-dtrace' '--disable-phpdbg' '--enable-zend-signals' '--without-iconv'
checking for grep that handles long lines and -e... /usr/bin/grep
checking for egrep... /usr/bin/grep -E
checking for a sed that does not truncate output... /usr/bin/sed
checking build system type... x86_64-apple-darwin16.6.0
checking host system type... x86_64-apple-darwin16.6.0
checking target system type... x86_64-apple-darwin16.6.0
checking for cc... cc
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 cc accepts -g... yes
checking for cc option to accept ISO C89... none needed
checking how to run the C preprocessor... cc -E
checking for icc... no
checking for suncc... no
checking whether cc understands -c and -o together... yes
checking how to run the C preprocessor... cc -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 minix/config.h usability... no
checking minix/config.h presence... no
checking for minix/config.h... no
checking whether it is safe to define __EXTENSIONS__... yes
checking whether ln -s works... yes
checking for system library directory... lib
checking whether to enable runpaths... yes
checking if compiler supports -R... no
checking if compiler supports -Wl,-rpath,... yes
checking for gawk... no
checking for nawk... no
checking for awk... awk
checking if awk is broken... no
checking for bison... bison -y
checking for bison version... invalid
configure: WARNING: This bison version is not supported for regeneration of the Zend/PHP parsers (found: 2.3, min: 204, excluded: ).
checking for re2c... no
configure: WARNING: You will need re2c 0.13.4 or later if you want to regenerate PHP parsers.
checking whether to enable computed goto gcc extension with re2c... no
checking whether cc supports -no-cpp-precomp... yes
checking whether to force non-PIC code in shared modules... no
checking whether /dev/urandom exists... yes
checking whether /dev/arandom exists... no
checking for global register variables support... no
checking for pthreads_cflags... -pthread
checking for pthreads_lib... pthread

Configuring SAPI modules
checking for Apache 2.0 handler-module support via DSO through APXS... yes
checking for setproctitle... no
checking sys/pstat.h usability... no
checking sys/pstat.h presence... no
checking for sys/pstat.h... no
checking for PS_STRINGS... no
checking for CLI build... yes
checking for embedded SAPI library support... no
checking for FPM build... yes
checking for setenv... yes
checking for clearenv... no
checking for setproctitle... (cached) no
checking for library containing socket... none required
checking for library containing inet_addr... none required
checking errno.h usability... yes
checking errno.h presence... yes
checking for errno.h... yes
checking fcntl.h usability... yes
checking fcntl.h presence... yes
checking for fcntl.h... yes
checking stdio.h usability... yes
checking stdio.h presence... yes
checking for stdio.h... yes
checking for stdlib.h... (cached) yes
checking for unistd.h... (cached) yes
checking sys/uio.h usability... yes
checking sys/uio.h presence... yes
checking for sys/uio.h... yes
checking sys/select.h usability... yes
checking sys/select.h presence... yes
checking for sys/select.h... 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 arpa/inet.h usability... yes
checking arpa/inet.h presence... yes
checking for arpa/inet.h... yes
checking netinet/in.h usability... yes
checking netinet/in.h presence... yes
checking for netinet/in.h... yes
checking sysexits.h usability... yes
checking sysexits.h presence... yes
checking for sysexits.h... yes
checking for prctl... no
checking for clock_gettime... yes
checking for ptrace... yes
checking whether ptrace works... no
checking for mach_vm_read... yes
checking if gcc supports __sync_bool_compare_and_swap... yes
checking for TCP_INFO... no
checking for SO_LISTENQLEN... no
checking for sysconf... yes
checking for times... yes
checking for kqueue... yes
checking for port framework... no
checking for /dev/poll... no
checking for epoll... no
checking for poll... yes
checking for select... yes
checking for apparmor... no
checking for LiteSpeed support... no
checking for phpdbg support... no
checking for phpdbg web SAPI support... no
checking for phpdbg debug build... no
checking for CGI build... yes
checking for socklen_t in sys/socket.h... yes
checking for sun_len in sys/un.h... yes
checking whether cross-process locking is required by accept()... no
checking for chosen SAPI module... apache2handler
checking for executable SAPI binaries...  cli fpm cgi

Running system checks
checking for sendmail... /usr/sbin/sendmail
checking whether system uses EBCDIC... no
checking whether byte ordering is bigendian... no
checking whether writing to stdout works... This is the test message -- yes
checking for socket... yes
checking for socketpair... yes
checking for htonl... yes
checking for gethostname... yes
checking for gethostbyaddr... yes
checking for yp_get_default_domain... yes
checking for dlopen... yes
checking for sin in -lm... yes
checking for inet_aton... yes
checking for ANSI C header files... (cached) yes
checking for dirent.h that defines DIR... yes
checking for library containing opendir... none required
checking for inttypes.h... (cached) yes
checking for stdint.h... (cached) yes
checking for dirent.h... yes
checking for ApplicationServices/ApplicationServices.h... yes
checking for sys/param.h... yes
checking for sys/types.h... (cached) yes
checking for sys/time.h... (cached) yes
checking for netinet/in.h... (cached) yes
checking for alloca.h... yes
checking for arpa/inet.h... (cached) yes
checking for arpa/nameser.h... yes
checking for assert.h... yes
checking for crypt.h... no
checking for dns.h... yes
checking for fcntl.h... (cached) yes
checking for grp.h... yes
checking for ieeefp.h... no
checking for langinfo.h... yes
checking for limits.h... yes
checking for locale.h... yes
checking for monetary.h... yes
checking for netdb.h... yes
checking for pwd.h... yes
checking for resolv.h... yes
checking for signal.h... yes
checking for stdarg.h... yes
checking for stdlib.h... (cached) yes
checking for string.h... (cached) yes
checking for syslog.h... yes
checking for sysexits.h... (cached) yes
checking for sys/ioctl.h... yes
checking for sys/file.h... yes
checking for sys/mman.h... yes
checking for sys/mount.h... yes
checking for sys/poll.h... yes
checking for sys/resource.h... yes
checking for sys/select.h... (cached) yes
checking for sys/socket.h... (cached) yes
checking for sys/stat.h... (cached) yes
checking for sys/statfs.h... no
checking for sys/statvfs.h... yes
checking for sys/vfs.h... no
checking for sys/sysexits.h... no
checking for sys/varargs.h... no
checking for sys/wait.h... yes
checking for sys/loadavg.h... no
checking for termios.h... yes
checking for unistd.h... (cached) yes
checking for unix.h... no
checking for utime.h... yes
checking for sys/utsname.h... yes
checking for sys/ipc.h... yes
checking for dlfcn.h... yes
checking for assert.h... (cached) yes
checking for fopencookie... no
checking for broken getcwd... no
checking for broken libc stdio... no
checking whether struct tm is in sys/time.h or time.h... time.h
checking for struct tm.tm_zone... yes
checking for missing declarations of reentrant functions... done
checking for fclose declaration... ok
checking for tm_gmtoff in struct tm... yes
checking for struct flock... yes
checking for socklen_t... yes
checking size of size_t... 8
checking size of long long... 8
checking size of long long int... 8
checking size of long... 8
checking size of int... 4
checking size of intmax_t... 8
checking size of ssize_t... 8
checking size of ptrdiff_t... 8
checking size of short... 2
checking size of int... (cached) 4
checking size of long... (cached) 8
checking size of long long... (cached) 8
checking for int8... no
checking for int16... no
checking for int32... no
checking for int64... no
checking for int8_t... yes
checking for int16_t... yes
checking for int32_t... yes
checking for int64_t... yes
checking for uint8... no
checking for uint16... no
checking for uint32... no
checking for uint64... no
checking for uint8_t... yes
checking for uint16_t... yes
checking for uint32_t... yes
checking for uint64_t... yes
checking for u_int8_t... yes
checking for u_int16_t... yes
checking for u_int32_t... yes
checking for u_int64_t... yes
checking for __builtin_expect... yes
checking for __builtin_clz... yes
checking for __builtin_ctzl... yes
checking for __builtin_ctzll... yes
checking for struct stat.st_blksize... yes
checking for struct stat.st_blocks... yes
checking for struct stat.st_rdev... yes
checking for size_t... yes
checking for uid_t in sys/types.h... yes
checking for struct sockaddr_storage... yes
checking for field sa_len in struct sockaddr... yes
checking for IPv6 support... yes
checking for vprintf... yes
checking for _doprnt... no
checking for alphasort... yes
checking for asctime_r... yes
checking for chroot... yes
checking for ctime_r... yes
checking for cuserid... no
checking for crypt... yes
checking for flock... yes
checking for ftok... yes
checking for funopen... yes
checking for gai_strerror... yes
checking for gcvt... yes
checking for getloadavg... yes
checking for getlogin... yes
checking for getprotobyname... yes
checking for getprotobynumber... yes
checking for getservbyname... yes
checking for getservbyport... yes
checking for gethostname... (cached) yes
checking for getrusage... yes
checking for gettimeofday... yes
checking for gmtime_r... yes
checking for getpwnam_r... yes
checking for getgrnam_r... yes
checking for getpwuid_r... yes
checking for grantpt... yes
checking for inet_ntoa... yes
checking for inet_ntop... yes
checking for inet_pton... yes
checking for isascii... yes
checking for link... yes
checking for localtime_r... yes
checking for lockf... yes
checking for lchown... yes
checking for lrand48... yes
checking for memcpy... yes
checking for memmove... yes
checking for mkstemp... yes
checking for mmap... yes
checking for nl_langinfo... yes
checking for perror... yes
checking for poll... yes
checking for ptsname... yes
checking for putenv... yes
checking for realpath... yes
checking for random... yes
checking for rand_r... yes
checking for scandir... yes
checking for setitimer... yes
checking for setlocale... yes
checking for localeconv... yes
checking for setenv... (cached) yes
checking for setpgid... yes
checking for setsockopt... yes
checking for setvbuf... yes
checking for shutdown... yes
checking for sin... yes
checking for snprintf... yes
checking for srand48... yes
checking for srandom... yes
checking for statfs... yes
checking for statvfs... yes
checking for std_syslog... no
checking for strcasecmp... yes
checking for strcoll... yes
checking for strdup... yes
checking for strerror... yes
checking for strftime... yes
checking for strnlen... yes
checking for strptime... yes
checking for strstr... yes
checking for strtok_r... yes
checking for symlink... yes
checking for tempnam... yes
checking for tzset... yes
checking for unlockpt... yes
checking for unsetenv... yes
checking for usleep... yes
checking for utime... yes
checking for vsnprintf... yes
checking for vasprintf... yes
checking for asprintf... yes
checking for nanosleep... yes
checking for nanosleep in -lrt... no
checking for __nanosleep in -lrt... no
checking for getaddrinfo... yes
checking for __sync_fetch_and_add... yes
checking for strlcat... yes
checking for strlcpy... yes
checking for getopt... yes
checking for utime.h... (cached) yes
checking whether utime accepts a null argument... yes
checking for working alloca.h... yes
checking for alloca... yes
checking for declared timezone... yes
checking for type of reentrant time-related functions... POSIX
checking for readdir_r... yes
checking for type of readdir_r... POSIX
checking for in_addr_t... yes
checking for crypt_r... no

General settings
checking whether to include gcov symbols... no
checking whether to include debugging symbols... no
checking layout of installed files... PHP
checking path to configuration file... /usr/local/etc/php/5.6
checking where to scan for configuration files... /usr/local/etc/php/5.6/conf.d
checking whether to enable PHP's own SIGCHLD handler... no
checking whether to explicitly link against libgcc... no
checking whether to enable short tags by default... yes
checking whether to enable dmalloc... no
checking whether to enable IPv6 support... yes
checking whether to enable DTrace support... yes
checking sys/sdt.h usability... yes
checking sys/sdt.h presence... yes
checking for sys/sdt.h... yes
checking how big to make fd sets... using system default

Configuring extensions
checking size of long... (cached) 8
checking size of int... (cached) 4
checking for int32_t... yes
checking for uint32_t... yes
checking for sys/types.h... (cached) yes
checking for inttypes.h... (cached) yes
checking for stdint.h... (cached) yes
checking for string.h... (cached) yes
checking for stdlib.h... (cached) yes
checking for strtoll... yes
checking for atoll... yes
checking for strftime... (cached) yes
checking for gettimeofday... (cached) yes
checking whether to enable LIBXML support... yes
checking libxml2 install dir... /usr/local/opt/libxml2
checking for xml2-config path... /usr/local/opt/libxml2/bin/xml2-config
checking whether libxml build works... yes
checking for OpenSSL support... yes
checking for Kerberos support... /usr
checking whether to use system default cipher list instead of hardcoded value... no
checking for krb5-config... /usr/bin/krb5-config
checking for RAND_egd... no
checking for pkg-config... /usr/local/bin/pkg-config
checking for OpenSSL version... >= 1.0.1
checking for CRYPTO_free in -lcrypto... yes
checking for SSL_CTX_set_ssl_version in -lssl... yes
checking for PCRE library to use... bundled
checking whether to enable PCRE JIT functionality... yes
checking whether to enable the SQLite3 extension... yes
checking bundled sqlite3 library... yes
checking for ZLIB support... yes
checking if the location of ZLIB install directory is defined... no
checking for zlib version >= 1.2.0.4... 1.2.8
checking for gzgets in -lz... yes
checking whether to enable bc style precision math functions... yes
checking for BZip2 support... yes
checking for BZ2_bzerror in -lbz2... yes
checking whether to enable calendar conversion support... yes
checking whether to enable ctype functions... yes
checking for cURL support... yes
checking for cURL in default path... found in /usr
checking for cURL 7.10.5 or greater... libcurl 7.51.0
checking for SSL support in libcurl... yes
checking how to run the C preprocessor... cc -E
checking for openssl support in libcurl... no
checking for gnutls support in libcurl... no
checking for curl_easy_perform in -lcurl... yes
checking for curl_easy_strerror in -lcurl... yes
checking for curl_multi_strerror in -lcurl... yes
checking for QDBM support... no
checking for GDBM support... no
checking for dbm_open in -lndbm... no
checking for dbm_open in -ldb1... no
checking for dbm_open in -lc... yes
checking for NDBM support... yes
checking for TCADB support... no
checking for Berkeley DB4 support... no
checking for Berkeley DB3 support... no
checking for Berkeley DB2 support... no
checking for DB1 support... no
checking for DBM support... no
checking for CDB support... builtin
checking for INI File support... builtin
checking for FlatFile support... builtin
checking whether to enable DBA interface... yes
checking whether to enable DOM support... yes
checking for xml2-config path... (cached) /usr/local/opt/libxml2/bin/xml2-config
checking whether libxml build works... (cached) yes
checking for ENCHANT support... no
checking whether to enable EXIF (metadata from images) support... yes
checking for fileinfo support... yes
checking for strcasestr... yes
checking for utimes... yes
checking for strndup... yes
checking whether to enable input filter support... yes
checking pcre install prefix... no
checking whether to enable FTP support... yes
checking OpenSSL dir for FTP... no
checking for OpenSSL version... >= 1.0.1
checking for CRYPTO_free in -lcrypto... (cached) yes
checking for SSL_CTX_set_ssl_version in -lssl... (cached) yes
checking for GD support... yes
checking for the location of libwebp... no
checking for the location of libjpeg... /usr/local/opt/jpeg
checking for the location of libpng... /usr/local/opt/libpng
checking for the location of libXpm... no
checking for FreeType 2... /usr/local/opt/freetype
checking whether to enable truetype string function in GD... yes
checking whether to enable JIS-mapped Japanese font support in GD... no
If configure fails try --with-webp-dir=<DIR>
checking for jpeg_read_header in -ljpeg... yes
checking for png_write_image in -lpng... yes
If configure fails try --with-xpm-dir=<DIR>
checking for fabsf... yes
checking for floorf... yes
checking for GNU gettext support... yes
checking for bindtextdomain in -lintl... yes
checking for ngettext in -lintl... yes
checking for dngettext in -lintl... yes
checking for dcngettext in -lintl... yes
checking for bind_textdomain_codeset in -lintl... yes
checking for GNU MP support... no
checking for mhash support... yes
checking whether to enable hash support... yes
checking whether byte ordering is bigendian... (cached) no
checking size of short... (cached) 2
checking size of int... (cached) 4
checking size of long... (cached) 8
checking size of long long... (cached) 8
checking for iconv support... no
checking for IMAP support... no
checking for IMAP Kerberos support... /usr
checking for IMAP SSL support... no
checking for Firebird support... no
checking whether to enable internationalization support... no
checking whether to enable JavaScript Object Serialization support... yes
checking for ANSI C header files... (cached) yes
checking for LDAP support... no
checking for LDAP Cyrus SASL support... no
checking whether to enable multibyte string support... yes
checking whether to enable multibyte regex support... yes
checking whether to check multibyte regex backtrack... yes
checking for external libmbfl... no
checking for external oniguruma... no
checking for variable length prototypes and stdarg.h... no
checking for stdlib.h... (cached) yes
checking for string.h... (cached) yes
checking for strings.h... (cached) yes
checking for unistd.h... (cached) yes
checking for sys/time.h... (cached) yes
checking sys/times.h usability... yes
checking sys/times.h presence... yes
checking for sys/times.h... yes
checking for stdarg.h... (cached) yes
checking size of int... (cached) 4
checking size of short... (cached) 2
checking size of long... (cached) 8
checking for an ANSI C-conforming const... yes
checking whether time.h and sys/time.h may both be included... yes
checking for working alloca.h... (cached) yes
checking for alloca... (cached) yes
checking for working memcmp... no
checking for stdarg.h... (cached) yes
checking for mcrypt support... no
checking for MySQLi support... yes
checking whether to enable embedded MySQLi support... no
checking for specified location of the MySQL UNIX socket... /tmp/mysql.sock
checking for MySQL UNIX socket location... /tmp/mysql.sock
checking for Oracle Database OCI8 support... no
checking for Adabas support... no
checking for SAP DB support... no
checking for Solid support... no
checking for IBM DB2 support... no
checking for ODBCRouter.com support... no
checking for Empress support... no
checking for Empress local access support... no
checking for Birdstep support... no
checking for a custom ODBC support... no
checking for iODBC support... no
checking for Easysoft ODBC-ODBC Bridge support... no
checking for unixODBC support... yes
checking whether to enable Zend OPcache support... no
checking whether to enable file based caching... yes
checking whether to enable copying PHP CODE pages into HUGE PAGES... yes
checking whether to enable pcntl support... yes
checking for fork... no
configure: error: pcntl: fork() not supported by this platform