updated for version 7.4.508
Problem:    When generating ja.sjis.po the header is not correctly adjusted.
Solution:   Check for the right header string. (Ken Takata)
Added tag v7-4-508 for changeset 65df2fba429b
updated for version 7.4.509
Problem:    Users are not aware their encryption is weak.
Solution:   Give a warning when prompting for the key.
Added tag v7-4-509 for changeset 60659773c73b
updated for version 7.4.510
Problem:    "-fwrapv" argument breaks use of cproto.
Solution:   Remove the alphabetic arguments in a drastic way.
Added tag v7-4-510 for changeset 05850b74218b
updated for version 7.4.511
Problem:    Generating proto for if_ruby.c uses type not defined elsewhere.
Solution:   Do not generate a prototype for
	    rb_gc_writebarrier_unprotect_promoted()
Added tag v7-4-511 for changeset 7623d953d3bc
updated for version 7.4.512
Problem:    Cannot generate prototypes for Win32 files and VMS.
Solution:   Add typedefs and #ifdef
Added tag v7-4-512 for changeset 9f9058aeba0d
Merge remote-tracking branch 'upstream/master' into all