ltdl, use LTDL_INIT's "recursive" mode

This decreases the distdir size about 1.3 MB and increases configure
speed.
Note we also removed unused check for ltdl.h
bldchn, AC_CONFIG_HEADER is obsolete since a long time
ltdl, use LTDLINCL instead of obsolete INCLTDL
style init script
ltdl, add make deps on included libltdl
Merge branch 'contrib'

* contrib:
  style init script
Merge remote-tracking branch 'rudi/bld/cosmetics'

* rudi/bld/cosmetics:
  ltdl, add make deps on included libltdl
  ltdl, use LTDLINCL instead of obsolete INCLTDL
  bldchn, AC_CONFIG_HEADER is obsolete since a long time
  ltdl, use LTDL_INIT's "recursive" mode
minor, turn AC_LANG_WERROR off permanently upon SXE_CHECK_LIBTOOL

Signed-off-by: Sebastian Freundt <freundt@fresse.org>
chore, prefer xiar over ar when assembling lib archives

Signed-off-by: Sebastian Freundt <freundt@fresse.org>
chore, kick not-so-useful checks for LDFLAGS

Signed-off-by: Sebastian Freundt <freundt@fresse.org>

Conflicts:
	configure.ac
chore, kick the sxe-linker.m4 macro package altogether

Signed-off-by: Sebastian Freundt <freundt@fresse.org>
Merge branch 'bld/dist'

* bld/dist:
  chore, kick the sxe-linker.m4 macro package altogether
  chore, kick not-so-useful checks for LDFLAGS
  chore, prefer xiar over ar when assembling lib archives
  minor, turn AC_LANG_WERROR off permanently upon SXE_CHECK_LIBTOOL
build, use the more portable _POSIX_HOST_NAME_MAX
build, struct sockaddr needs sys/socket.h
Merge remote-tracking branch 'rudi/fixes'

* rudi/fixes:
  build, struct sockaddr needs sys/socket.h
  build, use the more portable _POSIX_HOST_NAME_MAX