Fix configure error

This patch fixes configure error on some systems such as Alpine.

```
 line 3472: test: =: unary operator expected
```

One of the fixes has been suggested also here already:
https://bugs.php.net/bug.php?id=39835

Thank you for considering merging this.

Author: petk

NEWS

@@ -5,6 +5,7 @@ PHP                                                                        NEWS
 - Core:
   . Fixed bug #74780 (parse_url() borken when query string contains colon). 
     (jhdxr)
+  . Fixed bug #74761 (Unary operator expected error on some systems). (petk)
 
 - SPL:
   . Fixed bug #73471 (PHP freezes with AppendIterator). (jhdxr)

acinclude.m4

@@ -2687,7 +2687,7 @@ EOF
   done
 
   echo "'[$]0' \\" >> $1
-  if test `expr -- [$]0 : "'.*"` = 0; then
+  if test `expr " [$]0" : " '.*"` = 0; then
     CONFIGURE_COMMAND="$CONFIGURE_COMMAND '[$]0'"
   else 
     CONFIGURE_COMMAND="$CONFIGURE_COMMAND [$]0"