Refactor undefining PACKAGE_* symbols

Instead of patching configuration headers template generated by
the given tools - autoheader, this moves patching these symbols to
the configure step before creating and invoking the config.status
and before the configuration header file is generated from the
patched template.

Closes GH-4374

build/build.mk

@@ -34,9 +34,7 @@ configure: configure.ac $(PHP_M4_FILES)
 
 $(config_h_in): configure
 # Explicitly remove target since autoheader does not seem to work correctly
-# otherwise (timestamps are not updated). Also disable PACKAGE_* symbols in the
-# generated php_config.h.in template.
+# otherwise (timestamps are not updated).
 	@echo rebuilding $@
 	@rm -f $@
 	@$(PHP_AUTOHEADER) $(PHP_AUTOCONF_FLAGS)
-	@sed -e 's/^#undef PACKAGE_[^ ]*/\/\* & \*\//g' < $@ > $@.tmp && mv $@.tmp $@

build/php.m4

@@ -2715,3 +2715,19 @@ int main() {
   AC_DEFINE_UNQUOTED(AS_TR_CPP([PHP_HAVE_$1_INSTRUCTIONS]),
    [$have_ext_instructions], [Whether the compiler supports $1 instructions])
 ])
+
+dnl
+dnl PHP_PATCH_CONFIG_HEADERS([FILE])
+dnl
+dnl PACKAGE_* symbols are automatically defined by Autoconf. When including
+dnl configuration header, warnings about redefined symbols are emitted for such
+dnl symbols if they are defined by multiple libraries. This disables all
+dnl PACKAGE_* symbols in the generated configuration header template FILE. For
+dnl example, main/php_config.h.in for PHP or config.h.in for PHP extensions.
+dnl
+AC_DEFUN([PHP_PATCH_CONFIG_HEADERS], [
+  AC_MSG_NOTICE([patching $1])
+
+  $SED -e 's/^#undef PACKAGE_[^ ]*/\/\* & \*\//g' < $srcdir/$1 \
+    > $srcdir/$1.tmp && mv $srcdir/$1.tmp $srcdir/$1
+])

configure.ac

@@ -27,6 +27,7 @@ PHP_CONFIG_NICE(config.nice)
 PHP_CANONICAL_HOST_TARGET
 
 AC_CONFIG_HEADERS([main/php_config.h])
+
 AH_TOP([
 #ifndef PHP_CONFIG_H
 #define PHP_CONFIG_H
@@ -1585,6 +1586,9 @@ $PHP_OUTPUT_FILES"
 
 dnl Generate build files.
 AC_CONFIG_FILES([$ALL_OUTPUT_FILES])
+
+AC_CONFIG_COMMANDS_PRE([PHP_PATCH_CONFIG_HEADERS([main/php_config.h.in])])
+
 AC_CONFIG_COMMANDS([default],[
 cat <<X
 

scripts/phpize.in

@@ -163,10 +163,6 @@ phpize_autotools()
 
   $PHP_AUTOCONF   || exit 1
   $PHP_AUTOHEADER || exit 1
-
-  # Disable PACKAGE_* symbols in config.h.in
-  $SED -e 's/^#undef PACKAGE_[^ ]*/\/\* & \*\//g' < config.h.in > config.h.in.tmp
-  mv config.h.in.tmp config.h.in
 }
 
 # Main script

scripts/phpize.m4

@@ -210,4 +210,6 @@ test -d modules || $php_shtool mkdir modules
 
 AC_CONFIG_HEADERS([config.h])
 
+AC_CONFIG_COMMANDS_PRE([PHP_PATCH_CONFIG_HEADERS([config.h.in])])
+
 AC_OUTPUT