Log Message:
devel/smake: Update to 1.3nb13

New features with AN-2020-07-18:
- Makefile system: changed several "echo MAKING... && sh ./MKLINKS"
  into "echo MAKING... ; sh ./MKLINKS"

  This allows an optimization in smake to avoid a call to sh -c "cmd".
  if the command is a simple command or a simple command prefixed by
  "echo something ;". Since 2012, we implement an inline echo command
  in smake to speed up makefile execution.

- smake: The -a option is now no longer missing in the smake -help
  output. This has been forgotten when the option has been added in March.

New features with AN-2020-08-12:
- autoconf: added a new test for the existence of <sys/auxv.h>

- autoconf: added new tests for Linux getauxval() and FreeBSD elf_aux_info()

- libschily: getexecpath.c now uses getauxval() on Linux and elf_aux_info()
  on FreeBSD. This was needed since readlink("/proc/curproc/file") on
  FreeBSD returns random values for hardlinked files, making it impossible
  to use the result in order to find out which behavior variant of a
  fat binary is requested.

- smake: Added some code to allow better debugging of MAKEFLAGS related
  problems.

- smake: we now use strdup() to remember the content of the MAKEFLAGS
  environment as the content of a pointer into the environment array
  did change unexpectedly on DJGPP.

  Thanks to a hint from Albert Wik.