ecpg regression test failures caused by window functions patch

It hadn't occurred to me to try the ecpg tests before committing the
window functions patch :-(.  It looks like those grammar additions have
resulted in whitespace changes in a lot of the test outputs.  Would you
confirm that there's nothing seriously wrong and update the output
files?

It strikes me that it might be a good idea to change cat2_str to not
insert a space when obviously not necessary, perhaps along the lines
of
 cat2_str(char *str1, char *str2) {     char * res_str    = (char *)mm_alloc(strlen(str1) + strlen(str2) + 2);
strcpy(res_str,str1);
 
-      strcat(res_str, " ");
+    if (strlen(str1) != 0 && strlen(str2) != 0)
+        strcat(res_str, " ");     strcat(res_str, str2);     free(str1);     free(str2);     return(res_str); }

It looks like this would reduce the vulnerability of the ecpg tests to
whitespace changes caused by "insignificant" grammar changes.
        regards, tom lane