Trim trailing whitespaces in build files

Some editors utilizing .editorconfig automatically trim whitespaces. For
convenience this patch removes whitespaces in certain build files:
- ext/*/config*.m4
- configure.ac
- acinclude.m4

scripts/phpize.m4

@@ -6,7 +6,7 @@ ifdef([AC_PRESERVE_HELP_ORDER], [AC_PRESERVE_HELP_ORDER], [])
 
 PHP_CONFIG_NICE(config.nice)
 
-dnl 
+dnl
 AC_DEFUN([PHP_EXT_BUILDDIR],[.])dnl
 AC_DEFUN([PHP_EXT_DIR],[""])dnl
 AC_DEFUN([PHP_EXT_SRCDIR],[$abs_srcdir])dnl
@@ -45,7 +45,7 @@ phpincludedir=`$PHP_CONFIG --include-dir 2>/dev/null`
 INCLUDES=`$PHP_CONFIG --includes 2>/dev/null`
 EXTENSION_DIR=`$PHP_CONFIG --extension-dir 2>/dev/null`
 PHP_EXECUTABLE=`$PHP_CONFIG --php-binary 2>/dev/null`
- 
+
 if test -z "$prefix"; then
   AC_MSG_ERROR([Cannot find php-config. Please use --with-php-config=PATH])
 fi