PHP 8.5.0: preserve_none check fails on macOS (undefined symbol fun as macOS uses _fun) #20546
Description
Description
While preparing PHP 8.5.0 release in Homebrew (Homebrew/homebrew-core#255299), I noticed that the new TAILCALL VM feature wasn't getting enabled on macOS.
From config.log, the error is
configure:81621: checking for preserve_none calling convention
configure:81715: clang -o conftest -g -O2 -ffp-contract=off -fvisibility=hidden -DNDEBUG -D_GNU_SOURCE -Wl,-rpath,/opt/homebrew/Cellar/openssl@3/3.6.0/lib -L/opt/homebrew/Cellar/openssl@3/3.6.0/lib -Wl,-rpath,/opt/homebrew/Cellar/pcre2/10.47/lib -L/opt/homebrew/Cellar/pcre2/10.47/lib -Wl,-rpath,/opt/homebrew/opt/sqlite/lib -L/opt/homebrew/opt/sqlite/lib -Wl,-rpath,/Library/Developer/CommandLineTools/SDKs/MacOSX26.sdk/usr/lib -L/Library/Developer/CommandLineTools/SDKs/MacOSX26.sdk/usr/lib -Wl,-rpath,/opt/homebrew/Cellar/curl/8.17.0/lib -L/opt/homebrew/Cellar/curl/8.17.0/lib -Wl,-rpath,/opt/homebrew/Cellar/gd/2.3.3_6/lib -L/opt/homebrew/Cellar/gd/2.3.3_6/lib -Wl,-rpath,/opt/homebrew/opt/gettext/lib -L/opt/homebrew/opt/gettext/lib -Wl,-rpath,/opt/homebrew/opt/gmp/lib -L/opt/homebrew/opt/gmp/lib -Wl,-rpath,/opt/homebrew/opt/openldap/lib -L/opt/homebrew/opt/openldap/lib -Wl,-rpath,/opt/homebrew/Cellar/oniguruma/6.9.10/lib -L/opt/homebrew/Cellar/oniguruma/6.9.10/lib -Wl,-rpath,/opt/homebrew/Cellar/unixodbc/2.3.14/lib -L/opt/homebrew/Cellar/unixodbc/2.3.14/lib -Wl,-rpath,/opt/homebrew/opt/freetds/lib -L/opt/homebrew/opt/freetds/lib -Wl,-rpath,/opt/homebrew/opt/libpq/lib -L/opt/homebrew/opt/libpq/lib -Wl,-rpath,/opt/homebrew/Cellar/net-snmp/5.9.4/lib -L/opt/homebrew/Cellar/net-snmp/5.9.4/lib -Wl,-rpath,/opt/homebrew/opt/openssl@3/lib -L/opt/homebrew/opt/openssl@3/lib -Wl,-rpath,/opt/homebrew/Cellar/libsodium/1.0.20/lib -L/opt/homebrew/Cellar/libsodium/1.0.20/lib -Wl,-rpath,/opt/homebrew/Cellar/argon2/20190702_1/lib -L/opt/homebrew/Cellar/argon2/20190702_1/lib -Wl,-rpath,/opt/homebrew/opt/tidy-html5/lib -L/opt/homebrew/opt/tidy-html5/lib -Wl,-rpath,/opt/homebrew/Cellar/libzip/1.11.4/lib -L/opt/homebrew/Cellar/libzip/1.11.4/lib conftest.c >&5
Undefined symbols for architecture arm64:
"fun", referenced from:
_test in conftest-4b4b9c.o
_main in conftest-4b4b9c.o
This can also be reproduced by just trying to manually compile - https://github.com/php/php-src/blob/php-8.5.0/Zend/Zend.m4#L479
The issue is due to macOS symbol being _fun not fun, e.g.
❯ clang -c test.c && nm -gU test.o | grep fun
0000000000000000 T _funLine 518 in ca7f556
Also, minor issue but there is a typo (preverve) which I noticed when trying to override the cache variable
Line 477 in 685e996
PHP Version
PHP 8.5.0 (cli) (built: Nov 18 2025 08:02:20) (NTS)
Copyright (c) The PHP Group
Built by Homebrew
Zend Engine v4.5.0, Copyright (c) Zend Technologies
with Zend OPcache v8.5.0, Copyright (c), by Zend Technologies
Operating System
macOS 26