Hi, I had the same problem when i `build and make` php(7.3.5) with zts. And my macOS version is 10.12.6.

clang: warning: argument unused during compilation: '-pthread' [-Wunused-command-line-argument]
Undefined symbols for architecture x86_64:
  "thread-local wrapper routine for _tsrm_ls_cache", referenced from:
      _zim_IntlDateFormatter___construct in dateformat_create.o
      _timezone_convert_to_datetimezone in timezone_class.o
      _zif_intlcal_from_date_time in calendar_methods.o
      _zif_intlcal_to_date_time in calendar_methods.o
      _php_intlgregcal_constructor_body(_zend_execute_data*, _zval_struct*, unsigned char) in gregoriancalendar_methods.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [sapi/cli/php] Error 1

I try to create a static PHP 7.1 binary with intl support:

./configure --prefix=/home/username --enable-static --enable-cli --disable-cgi --enable-mysqlnd --with-mysql --with-mysqli --with-curl --with-zlib --enable-mbstring --enable-calendar --with-gd --with-bz2 --enable-sockets --enable-ftp --with-gettext --with-xmlrpc --with-xsl --with-pdo-mysql --enable-mbregex --enable-exif --enable-bcmath --with-mhash --enable-zip --with-mcrypt --enable-soap --with-openssl
./configure --prefix=/home/www/cretaftp/php --enable-static --enable-cli --disable-cgi --enable-mysqlnd --with-mysqli --with-curl --with-zlib --enable-mbstring --enable-calendar --with-gd --with-bz2 --enable-sockets --enable-ftp --with-gettext --with-xmlrpc --with-xsl --with-pdo-mysql --enable-mbregex --enable-exif --enable-bcmath --with-mhash --enable-zip --with-mcrypt --enable-soap --with-openssl --enable-intl --with-layout=GNU

But when I run:

make

I get this:

ld: error: undefined symbol: std::__throw_length_error(char const*)
>>> referenced by stl_vector.h:1756 (/usr/local/lib/gcc9/include/c++/bits/stl_vector.h:1756)
>>> ext/intl/msgformat/.libs/msgformat_helpers.o:(std::vector<icu::Formattable, std::allocator<icu::Formattable> >::_M_default_append(unsigned long))

ld: error: undefined symbol: std::__throw_length_error(char const*)
>>> referenced by stl_vector.h:1756 (/usr/local/lib/gcc9/include/c++/bits/stl_vector.h:1756)
>>> ext/intl/msgformat/.libs/msgformat_helpers.o:(std::vector<icu::UnicodeString, std::allocator<icu::UnicodeString> >::_M_default_append(unsigned long))
cc: error: linker command failed with exit code 1 (use -v to see invocation)
*** Error code 1

Stop.

If I remove --enable-intl from the ./configure command the issue doesn't exist.

I forgot to write that I use FreeBSD.

I'm having the same issue trying to compile php 7.2.26 with intl (also tried 7.3.13) on MacOS 10.11.6.
Php 7.1.33 with intl compiles just fine.

The problem seems to be that MacOS and/or its compiler software doesn't fully support "thread_local", so the php developers need to update the TSRM/TSRM.h file and add an ifdef thing for darwin/macos that disables the use of the "thread_local" function on MacOS.

Changed this code in the file TSRM/TSRM.h:

#if defined(__cplusplus) && __cplusplus > 199711L
# define TSRM_TLS thread_local
#else
# ifdef TSRM_WIN32
#  define TSRM_TLS __declspec(thread)
# else
#  define TSRM_TLS __thread
# endif
#endif

to this:

#ifdef TSRM_WIN32
# define TSRM_TLS __declspec(thread)
#else
# define TSRM_TLS __thread
#endif

so now it's the same as in 7.1.33 and now it compiles just fine!