convert: add commandline.xargs(), use it in svn_sink class...
convert: add commandline.xargs(), use it in svn_sink class
Introduce commandline.xargs() to limit argument list with respect
to ARG_MAX bytes. If no ARG_MAX information available - use POSIX
required minimum of 4096 bytes.
Under Windows, while actual argument list length is limited to 32k,
shells impose their own limits on command line length, down to 2047 bytes
for cmd.exe under Windows NT/2k and about 2500 bytes for older 4nt.exe.
See
http://support.microsoft.com/kb/830473 for details about cmd.exe
limitations.
Since ARG_MAX is limit for argument list and environment, we reserve half
of it and one byte for environment variables. This way with default ARG_MAX
(4096 bytes) we get value 2047 bytes which is OK for Windows too.
