ftp(1) will never attempt to set the modification date of any file retrieved by http[s]

[a dog]

>Synopsis:      ftp(1) will never attempt to set the modification date of any 
>file retrieved by http[s]
>Category:      user
>Environment:
        System      : OpenBSD 7.3
        Details     : OpenBSD 7.3-current (GENERIC.MP) #1259: Fri Jun 23 
09:13:33 MDT 2023
                         
dera...@amd64.openbsd.org:/usr/src/sys/arch/amd64/compile/GENERIC.MP

        Architecture: OpenBSD.amd64
        Machine     : amd64
>Description:
        ftp(1) will always act as if the Last-Modified header returned
        by the server is invalid, and set server_timestamps to 0 on line
        989 of usr.bin/ftp/fetch.c.  This is because the space following
        the colon is not stripped, and therefore strptime(3) will see
        something resembling " Sun, 25 Jun 2023 21:38:42 GMT" -
        otherwise valid but beginning with a space.  The end result is
        that file modification stamps will never be set, as if -u had
        been specified.
>How-To-Repeat:
        1) Pick any URL that returns a Last-Modified which is valid and
           not equal to the time of retrieval,
        2) Now retrieve the same URL using ftp(1).  The modification
           date is supposed to be set to the value returned by the
           server, but will instead be equal to the time the file was
           closed by ftp(1).
>Fix:
        Thankfully simple.  Please see proposed patch below.

diff --git i/usr.bin/ftp/fetch.c w/usr.bin/ftp/fetch.c
index 0ba7ad4d099..b6d6f4d775a 100644
--- i/usr.bin/ftp/fetch.c
+++ w/usr.bin/ftp/fetch.c
@@ -984,6 +984,7 @@ noslash:
                } else if (strncasecmp(cp, LAST_MODIFIED,
                            sizeof(LAST_MODIFIED) - 1) == 0) {
                        cp += sizeof(LAST_MODIFIED) - 1;
+                       cp += strspn(cp, " \t");
                        cp[strcspn(cp, "\t")] = '\0';
                        if (strptime(cp, "%a, %d %h %Y %T %Z", &lmt) == NULL)
                                server_timestamps = 0;