Autotools: Quote AC_SUBST arguments (#14743)

Author: petk

configure.ac

@@ -1438,18 +1438,18 @@ exec_prefix=$old_exec_prefix
 libdir=$old_libdir
 datadir=$old_datadir
 
-AC_SUBST(INCLUDE_PATH)
-AC_SUBST(EXPANDED_PEAR_INSTALLDIR)
-AC_SUBST(EXPANDED_EXTENSION_DIR)
-AC_SUBST(EXPANDED_BINDIR)
-AC_SUBST(EXPANDED_SBINDIR)
-AC_SUBST(EXPANDED_MANDIR)
-AC_SUBST(EXPANDED_LIBDIR)
-AC_SUBST(EXPANDED_DATADIR)
-AC_SUBST(EXPANDED_SYSCONFDIR)
-AC_SUBST(EXPANDED_LOCALSTATEDIR)
-AC_SUBST(EXPANDED_PHP_CONFIG_FILE_PATH)
-AC_SUBST(EXPANDED_PHP_CONFIG_FILE_SCAN_DIR)
+AC_SUBST([INCLUDE_PATH])
+AC_SUBST([EXPANDED_PEAR_INSTALLDIR])
+AC_SUBST([EXPANDED_EXTENSION_DIR])
+AC_SUBST([EXPANDED_BINDIR])
+AC_SUBST([EXPANDED_SBINDIR])
+AC_SUBST([EXPANDED_MANDIR])
+AC_SUBST([EXPANDED_LIBDIR])
+AC_SUBST([EXPANDED_DATADIR])
+AC_SUBST([EXPANDED_SYSCONFDIR])
+AC_SUBST([EXPANDED_LOCALSTATEDIR])
+AC_SUBST([EXPANDED_PHP_CONFIG_FILE_PATH])
+AC_SUBST([EXPANDED_PHP_CONFIG_FILE_SCAN_DIR])
 AC_SUBST([PHP_INSTALLED_SAPIS])
 AC_SUBST([SAPI_LIBNAME_SHARED])
 AC_SUBST([SAPI_LIBNAME_STATIC])
@@ -1620,7 +1620,7 @@ PHP_CONFIGURE_PART(Configuring libtool)
 
 dnl Silence warning: `ar: 'u' modifier ignored since 'D' is the default`
 dnl See https://github.com/php/php-src/pull/3017
-AC_SUBST(AR_FLAGS, [cr])
+AC_SUBST([AR_FLAGS], [cr])
 
 dnl Only allow AC_PROG_CXX and AC_PROG_CXXCPP if they are explicitly called (by
 dnl PHP_REQUIRE_CXX). Otherwise AC_PROG_LIBTOOL fails if there is no working C++