Log Message:
devel/smake: Update to 1.5

Create OS rule for mips64eb architecture too (bulk build failed).

Changelog from AN-2021-05-19:
- smake: smake "MACRO += value" now works.

  smake did implement command line macros like "MACRO=value" since
  spring 1996 but did not yet support "MACRO +=value" as well.

- smake: smake "MACRO::=value" "MACRO:::=value", "MACRO \ 
+:= value"
  now work as well.

- smake: The man page now mentions the new command line macro operators
  ::=, :::=, += and +:=

- smake: Version bumped to 1.5

Changelog from AN-2021-06-07:
- smake: the MAKEFLAGS parser has been enhanced to understand the
  encoding used by the BSD make program "bmake". This is needed to
  support something like "bmake INS_BASE=xxx" on FreeBSD while
  compiling the schilytools.

  This parser enhancement also covers some incompatibilities with
  the MAKEFLAGS= values created by SunPro Make (e.g. a missing --
  before the make macro definitions are added).

  Thanks to Robert Clausecker for reporting.

- smake: The smake man page now also mentions SunPro make as dmake(1)
  and make(1s) in the "SEE ALSO" section.