Set AC_CONFIG_AUX_DIR to build directory

The Autoconf macro AC_CONFIG_AUX_DIR can set the location of the
auxiliary build tools such as config.guess, config.sub, and bundled
libtool scripts and moves these bundled files from the root directory
to the build subdirectory.

Additionally some changes in this context or as a part of obsoletion:
- The LT_TARGETS variable in build/build2.mk file was once used as a part
  of the Automake step. It's not used anymore and has been refactored to
  separate makedist script directly.
- ltconfig is not used anymore since libtool 1.4+
  cf8d156
- phpize file locations for the config.guess, config.sub, and ltmain.sh
  has been refactored accordingly.

CONTRIBUTING.md

@@ -96,7 +96,10 @@ locations.
  └─ build/                          # *nix build system files
     ├─ ax_check_compile_flag.m4     # https://github.com/autoconf-archive/autoconf-archive
     ├─ ax_gcc_func_attribute.m4     # https://github.com/autoconf-archive/autoconf-archive
+    ├─ 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
+    ├─ ltmain.sh                    # https://git.savannah.gnu.org/cgit/libtool.git
     ├─ shtool                       # https://www.gnu.org/software/shtool/
     └─ ...
  └─ ext/                            # PHP core extensions
@@ -170,8 +173,5 @@ locations.
  └─ win32/                          # Windows build system files
     ├─ cp_enc_map.c                 # Generated by `win32/cp_enc_map_gen.exe`
     └─ ...
- ├─ config.guess                    # https://git.savannah.gnu.org/cgit/config.git
- ├─ config.sub                      # https://git.savannah.gnu.org/cgit/config.git
- ├─ ltmain.sh                       # https://git.savannah.gnu.org/cgit/libtool.git
  └─ ...
 ```

build/build2.mk

@@ -18,8 +18,6 @@ include generated_lists
 
 TOUCH_FILES = mkinstalldirs install-sh missing
 
-LT_TARGETS = ltmain.sh config.guess config.sub
-
 config_h_in = main/php_config.h.in
 
 targets = $(TOUCH_FILES) configure $(config_h_in)

configure.ac

@@ -10,6 +10,7 @@ dnl -------------------------------------------------------------------------
 
 AC_PREREQ([2.68])
 AC_INIT(README.GIT-RULES)
+AC_CONFIG_AUX_DIR([build])
 AC_PRESERVE_HELP_ORDER
 
 PHP_CONFIG_NICE(config.nice)

makedist

@@ -44,7 +44,7 @@ if test "x$PHPROOT" = "x"; then
     PHPROOT=git@git.php.net:php-src.git;
 fi
 
-LT_TARGETS='ltconfig ltmain.sh config.guess config.sub'
+LT_TARGETS='build/ltmain.sh build/config.guess build/config.sub'
 
 if echo '\c' | grep -s c >/dev/null 2>&1
 then

scripts/Makefile.frag

@@ -9,19 +9,19 @@ BUILD_FILES = \
 	scripts/phpize.m4 \
 	build/scan_makefile_in.awk \
 	build/libtool.m4 \
+	build/ltmain.sh \
 	build/ax_check_compile_flag.m4 \
 	build/ax_gcc_func_attribute.m4 \
 	build/php_cxx_compile_stdcxx.m4 \
 	build/pkg.m4 \
 	Makefile.global \
 	acinclude.m4 \
-	ltmain.sh \
 	run-tests.php
 
 BUILD_FILES_EXEC = \
 	build/shtool \
-	config.guess \
-	config.sub
+	build/config.guess \
+	build/config.sub
 
 bin_SCRIPTS = phpize php-config
 man_PAGES = phpize php-config

scripts/phpize.in

@@ -9,11 +9,11 @@ includedir="`eval echo @includedir@`/php"
 builddir="`pwd`"
 SED="@SED@"
 
-FILES_BUILD="scan_makefile_in.awk shtool libtool.m4 ax_check_compile_flag.m4 ax_gcc_func_attribute.m4 php_cxx_compile_stdcxx.m4 pkg.m4"
-FILES="acinclude.m4 Makefile.global config.sub config.guess ltmain.sh run-tests*.php"
+FILES_BUILD="scan_makefile_in.awk shtool libtool.m4 ax_check_compile_flag.m4 ax_gcc_func_attribute.m4 php_cxx_compile_stdcxx.m4 pkg.m4 config.guess config.sub ltmain.sh"
+FILES="acinclude.m4 Makefile.global run-tests*.php"
 CLEAN_FILES="$FILES *.o *.lo *.la .libs/ build/ modules/ install-sh \
-	mkinstalldirs missing config.nice config.sub config.guess configure configure.ac \
-	aclocal.m4 config.h config.h.in conftest* ltmain.sh libtool config.cache autom4te.cache/ \
+	mkinstalldirs missing config.nice configure configure.ac \
+	aclocal.m4 config.h config.h.in conftest* libtool config.cache autom4te.cache/ \
 	config.log config.status Makefile Makefile.fragments Makefile.objects confdefs.h \
 	run-tests*.php tests/*.diff tests/*.exp tests/*.log tests/*.out tests/*.php"
 

scripts/phpize.m4

@@ -2,6 +2,7 @@ dnl This file becomes configure.ac for self-contained extensions.
 
 AC_PREREQ([2.68])
 AC_INIT(config.m4)
+AC_CONFIG_AUX_DIR([build])
 AC_PRESERVE_HELP_ORDER
 
 PHP_CONFIG_NICE(config.nice)