This prevents startup failures if ssl_ca has a large number of certificates.

Attempting to pipeline any commands with the AUTHENTICATE command resulted
in crash.

Fixes:
Panic: file istream.c: line 317 (i_stream_read_memarea): assertion failed: (old_size <= _stream->pos - _stream->skip)

Otherwise stats process startup can get into a loop.

Makes it easier to run with valgrind.

The flag has been removed, and the setting is now the default.

This follows the following commits in Dovecot:
lib-storage: Moved connection information in struct mail_user into separate struct mail_user_connection_data.
lib-storage: mail-user: Added more information about the client connection.

Call master_login_init() before master_service_init_finish(), which frees
all the data stack done in initialization.

This didn't normally cause any visible problems, because data stack wasn't
currently being used in a way that the strings were invalidated. However,
it was causing failures if --enable-devel-checks was used.

It's replaced with fd-util.h which is automatically included now.

path-util is a merge of realpath from Pigeonhole and abspath from core.

Used the following script:

C_FILES=`git ls-files *.c`
H_FILES=`git ls-files *.h`
for F in "$C_FILES $H_FILES"; do
        echo "$F"
  perl -p -i -e 's/safe_memset\(&\(?([^,]*)\)?,\s*0,\s*sizeof\(\g1\)\)/i_zero_safe(&$1)/g' $F
  perl -p -i -e 's/safe_memset\(([^,]*),\s*0,\s*sizeof\(\*\g1\)\)/i_zero_safe($1)/g' $F
  perl -p -i -e 's/memset\(&\(?([^,]*)\)?,\s*0,\s*sizeof\(\g1\)\)/i_zero(&$1)/g' $F
  perl -p -i -e 's/memset\(([^,]*),\s*0,\s*sizeof\(\*\g1\)\)/i_zero($1)/g' $F
done

managesieve: Managesieve used "managesieve" rather than "sieve" as login service name, which means that all managesieve-specific settings where ignored.

Most important change is that mail service_user was not freed.

This change matches a similar change in Dovecot for IMAP/POP3.
Also includes other small changes that make ManageSieve match IMAP implementation a little more closely.

"Running standalone?" check now uses a new DOVECOT_CHILD_PROCESS environment rather than GENERATION.
The GENERATION environment was already set in some systems for Java.