Bump libtool to serial 63 from 2.5.4 (php#21067)

The libtool 1.5.26 is bundled with PHP since the very early days of the
Autotools build system to ease the building process and avoid additional
dependency on the system Libtool. This updates the bundled libtool to
2.5.4 version.

Fixes and implementations:

- Fixed race conditions when building PHP in parallel ("cannot create
  .libs" warnings).
- Implements request https://bugs.php.net/70374 (Update libtool.m4)
- Fixes libtool eating -flto flags.
- Fixes phpGH-17310 (configure producing errors on macOS)
- Fixes phpGH-15946 (./configure error when building with NixOS)

Changes:
- Add a script to update autotools files.
- libtool is spread across multiple files; phpize is updated to handle
  this.
- Remove outdated hacks, i.e. for `ar`.
- Remove documentation references to external libtool, as we vendor it.
- `--with-pic` is now `--enable-pic`. Error out on the old flag.
- On macOS linker now uses -undefined dynamic_lookup flag for shared
  extensions and shared embed SAPI (libphp) instead of older
  '-undefined suppress -flat_namespace' combination.

Co-authored-by: Peter Kokot <peterkokot@gmail.com>

Author: NattyNarwhal

CONTRIBUTING.md

@@ -176,6 +176,7 @@ locations.
     ├─ config.guess                 # https://git.savannah.gnu.org/cgit/config.git
     ├─ config.sub                   # https://git.savannah.gnu.org/cgit/config.git
     ├─ libtool.m4                   # https://git.savannah.gnu.org/cgit/libtool.git
+    ├─ lt*.m4                       # https://git.savannah.gnu.org/cgit/libtool.git
     ├─ ltmain.sh                    # https://git.savannah.gnu.org/cgit/libtool.git
     ├─ pkg.m4                       # https://gitlab.freedesktop.org/pkg-config/pkg-config
     ├─ shtool                       # https://www.gnu.org/software/shtool/

README.md

@@ -49,7 +49,7 @@ sudo apt install -y pkg-config build-essential autoconf bison re2c libxml2-dev l
 On Fedora, you can install these using:
 
 ```shell
-sudo dnf install re2c bison autoconf make libtool ccache libxml2-devel sqlite-devel
+sudo dnf install re2c bison autoconf make ccache libxml2-devel sqlite-devel
 ```
 
 On MacOS, you can install these using `brew`:

UPGRADING.INTERNALS

@@ -89,6 +89,14 @@ PHP 8.6 INTERNALS UPGRADE NOTES
     zend_enum_fetch_case_id(zend_object*).
 
 - Unix build system changes:
+  . scripts/dev/update-autoconf.sh has been added to update config.*/libtool.
+  . libtool has been upgraded to 2.5.4 (serial 63), which fixes many bugs.
+  . As part of the upgrade to the new libtool:
+    . libtool is now spread across multiple files. phpize has been updated to
+      handle this.
+    . On macOS, libtool now uses -undefined dynamic_lookup for shared objects,
+      instead of -undefined suppress -flat_namespace.
+    . --with-pic is now --enable-pic. The old flag will result in an error.
   . Symbol HAVE_ST_BLOCKS has been removed from php_config.h (use
     HAVE_STRUCT_STAT_ST_BLOCKS).
 

Zend/Zend.m4

@@ -118,7 +118,7 @@ dnl Ugly hack to check if dlsym() requires a leading underscore in symbol name.
 dnl
 AC_DEFUN([ZEND_DLSYM_CHECK], [dnl
 AC_MSG_CHECKING([whether dlsym() requires a leading underscore in symbol names])
-_LT_AC_TRY_DLOPEN_SELF([AC_MSG_RESULT([no])], [
+_LT_TRY_DLOPEN_SELF([AC_MSG_RESULT([no])], [
   AC_MSG_RESULT([yes])
   AC_DEFINE([DLSYM_NEEDS_UNDERSCORE], [1],
     [Define to 1 if 'dlsym()' requires a leading underscore in symbol names.])