Autotools: Add min-version argument to PHP_PROG_PHP macro

UPGRADING.INTERNALS

@@ -181,6 +181,8 @@ PHP 8.4 INTERNALS UPGRADE NOTES
      anymore.
    - M4 macro PHP_SETUP_ICONV doesn't define the HAVE_ICONV symbol anymore.
    - M4 macro PHP_OUTPUT is obsolete (use AC_CONFIG_FILES).
+   - M4 macro PHP_PROG_SETUP now accepts an argument to set the minimum required
+     PHP version during the build.
    - 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

build/php.m4

@@ -1778,28 +1778,26 @@ AC_DEFUN([PHP_PROG_RE2C],[
   PHP_SUBST([RE2C_FLAGS])
 ])
 
-AC_DEFUN([PHP_PROG_PHP],[
-  AC_CHECK_PROG([PHP], [php], [php])
-
-  if test -n "$PHP"; then
-    AC_MSG_CHECKING([for php version])
-    php_version=$($PHP -v | head -n1 | cut -d ' ' -f 2 | cut -d '-' -f 1)
-    if test -z "$php_version"; then
-      php_version=0.0.0
-    fi
-    ac_IFS=$IFS; IFS="."
-    set $php_version
-    IFS=$ac_IFS
-    php_version_num=`expr [$]{1:-0} \* 10000 + [$]{2:-0} \* 100 + [$]{3:-0}`
-    dnl Minimum supported version for gen_stub.php is PHP 7.4.
-    if test "$php_version_num" -lt 70400; then
-      AC_MSG_RESULT([$php_version (too old)])
-      unset PHP
-    else
-      AC_MSG_RESULT([$php_version (ok)])
-    fi
-  fi
-  PHP_SUBST([PHP])
+dnl
+dnl PHP_PROG_PHP([min-version])
+dnl
+dnl Find PHP command-line interface SAPI on the system and check if version is
+dnl greater or equal to "min-version". If suitable version is found, the PHP
+dnl variable is set and substituted to a Makefile variable. Used for generating
+dnl files and running PHP utilities during the build.
+dnl
+AC_DEFUN([PHP_PROG_PHP],
+[m4_if([$1],, [php_required_version=7.4], [php_required_version=$1])
+AC_CHECK_PROG([PHP], [php], [php])
+AS_VAR_IF([PHP],,, [
+AC_MSG_CHECKING([for php version])
+php_version=$($PHP -v | head -n1 | cut -d ' ' -f 2)
+AS_VERSION_COMPARE([$php_version], [$php_required_version], [unset PHP])
+AS_VAR_IF([PHP],,
+  [AC_MSG_RESULT([$php_version (too old, install $php_required_version or later)])],
+  [AC_MSG_RESULT([$php_version (ok)])])
+])
+PHP_SUBST([PHP])
 ])
 
 dnl ----------------------------------------------------------------------------

configure.ac

@@ -155,7 +155,8 @@ dnl Checks for some support/generator progs.
 PHP_PROG_AWK
 PHP_PROG_BISON([3.0.0])
 PHP_PROG_RE2C([1.0.3], [--no-generation-date])
-PHP_PROG_PHP()
+dnl Find installed PHP. Minimum supported version for gen_stub.php is PHP 7.4.
+PHP_PROG_PHP([7.4])
 
 PHP_ARG_ENABLE([re2c-cgoto],
   [whether to enable computed goto extension with re2c],