Autotools: Simplify POSIX Threads check (php#14855)

The PTHREADS_CHECK is using cache variables so it is run only once early
during the configuration phase, before including SAPI and other M4
files. This removes the TSRM_CHECK_PTHREADS macro and moves the POSIX
Threads check after the PHP_THREAD_SAFETY variable is set in
configure.ac.

The check and error throw in PHP_BUILD_THREAD_SAFE is also joing into
this single check.

This removes the redundant tsrm.m4 file and PHP_CONFIGURE_PART call for
TSRM as it doesn't run any configuration checks anymore.

UPGRADING.INTERNALS

@@ -156,6 +156,7 @@ PHP 8.4 INTERNALS UPGRADE NOTES
    - PDO extensions in php-src don't have the include flag -I$pdo_cv_inc_path
      directory anymore.
    - M4 macro PHP_SETUP_OPENSSL doesn't accept the 3rd argument anymore.
+   - TSRM/tsrm.m4 file and its TSRM_CHECK_PTHREADS M4 macro have been removed.
    - Added pkg-config support to find libpq for the pdo_pgsql and pgsql
      extensions. The libpq paths can be customized with the PGSQL_CFLAGS and
      PGSQL_LIBS environment variables. When a directory argument is provided to

build/php.m4

@@ -724,12 +724,7 @@ dnl ----------------------------------------------------------------------------
 dnl
 dnl PHP_BUILD_THREAD_SAFE
 dnl
-AC_DEFUN([PHP_BUILD_THREAD_SAFE],[
-  enable_zts=yes
-  if test "$pthreads_working" != "yes"; then
-    AC_MSG_ERROR([ZTS currently requires working POSIX threads. We were unable to verify that your system supports Pthreads.])
-  fi
-])
+AC_DEFUN([PHP_BUILD_THREAD_SAFE], [enable_zts=yes])
 
 dnl
 dnl PHP_REQUIRE_CXX

configure.ac

@@ -11,7 +11,6 @@ m4_include([build/php_cxx_compile_stdcxx.m4])
 m4_include([build/php.m4])
 m4_include([build/pkg.m4])
 m4_include([TSRM/threads.m4])
-m4_include([TSRM/tsrm.m4])
 m4_include([Zend/Zend.m4])
 
 dnl Basic autoconf initialization, generation of config.nice.
@@ -871,6 +870,17 @@ else
   PHP_THREAD_SAFETY=no
 fi
 
+AS_VAR_IF([PHP_THREAD_SAFETY], [yes], [
+  AS_VAR_IF([pthreads_working], [yes], [],
+    [AC_MSG_ERROR([m4_normalize([
+      Unable to verify system support for POSIX Threads, which are required for
+      PHP thread safety (ZTS) build.
+    ])])])
+
+  AC_MSG_CHECKING([for POSIX threads])
+  AC_MSG_RESULT([yes])
+])
+
 PHP_ARG_ENABLE([rtld-now],
   [whether to dlopen extensions with RTLD_NOW instead of RTLD_LAZY],
   [AS_HELP_STRING([--enable-rtld-now],
@@ -1337,11 +1347,6 @@ PHP_ADD_INCLUDE([$abs_srcdir/TSRM])
 ZEND_EXTRA_LIBS="$LIBS"
 unset LIBS
 
-PHP_CONFIGURE_PART(Configuring TSRM)
-if test "$PHP_THREAD_SAFETY" = "yes"; then
-  TSRM_CHECK_PTHREADS
-fi
-
 EXTRA_LDFLAGS="$EXTRA_LDFLAGS $LDFLAGS"
 EXTRA_LDFLAGS_PROGRAM="$EXTRA_LDFLAGS_PROGRAM $LDFLAGS"
 EXTRA_LIBS="$EXTRA_LIBS $LIBS"