autoupdate: replace obsolete macros AC_CANONICAL_SYSTEM

- AC_CANONICAL_SYSTEM by:
    * AC_CANONICAL_HOST where host, and host_alias are needed
    * AC_CANONICAL_TARGET where target_alias is needed
  https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.72/autoconf.html#index-AC_005fCANONICAL_005fTARGET-1

config/acx.m4

@@ -107,9 +107,9 @@ AC_SUBST([target_subdir]) []dnl
 
 
 ####
-# _NCN_TOOL_PREFIXES:  Some stuff that oughtta be done in AC_CANONICAL_SYSTEM 
+# _NCN_TOOL_PREFIXES:  Some stuff that oughtta be done in AC_CANONICAL_TARGET
 # or AC_INIT.
-# These demand that AC_CANONICAL_SYSTEM be called beforehand.
+# These demand that AC_CANONICAL_HOST and AC_CANONICAL_TARGET be called beforehand.
 AC_DEFUN([_NCN_TOOL_PREFIXES],
 [ncn_tool_prefix=
 test -n "$host_alias" && ncn_tool_prefix=$host_alias-

config/lthostflags.m4

@@ -10,7 +10,7 @@ dnl Defines and AC_SUBSTs lt_host_flags
 
 
 AC_DEFUN([ACX_LT_HOST_FLAGS], [
-AC_REQUIRE([AC_CANONICAL_SYSTEM])
+AC_REQUIRE([AC_CANONICAL_HOST])
 
 case $host in
   *-cygwin* | *-mingw*)

configure.ac

@@ -70,14 +70,14 @@ ACX_NONCANONICAL_TARGET
 
 dnl Autoconf 2.5x and later will set a default program prefix if
 dnl --target was used, even if it was the same as --host.  Disable
-dnl that behavior.  This must be done before AC_CANONICAL_SYSTEM
+dnl that behavior.  This must be done before AC_CANONICAL_TARGET
 dnl to take effect.
 test "$host_noncanonical" = "$target_noncanonical" &&
   test "$program_prefix$program_suffix$program_transform_name" = \
     NONENONEs,x,x, &&
   program_transform_name=s,y,y,
 
-AC_CANONICAL_SYSTEM
+AC_CANONICAL_TARGET
 AC_ARG_PROGRAM
 
 m4_pattern_allow([^AS_FOR_TARGET$])dnl

gnulib/configure.ac

@@ -34,7 +34,7 @@ gl_EARLY
 AM_PROG_CC_STDC
 
 AC_CONFIG_AUX_DIR(..)
-AC_CANONICAL_SYSTEM
+AC_CANONICAL_TARGET
 
 gl_INIT
 

libbacktrace/configure.ac

@@ -37,7 +37,8 @@ if test -n "${with_target_subdir}"; then
   AM_ENABLE_MULTILIB(, ..)
 fi
 
-AC_CANONICAL_SYSTEM
+AC_CANONICAL_HOST
+AC_CANONICAL_TARGET
 target_alias=${target_alias-$host_alias}
 
 AC_USE_SYSTEM_EXTENSIONS

zlib/configure.ac

@@ -7,7 +7,7 @@ if test -n "${with_target_subdir}"; then
   AM_ENABLE_MULTILIB(, ..)
 fi
 
-AC_CANONICAL_SYSTEM
+AC_CANONICAL_TARGET
 
 # This works around an automake problem.
 mkinstalldirs="`cd $ac_aux_dir && ${PWDCMD-pwd}`/mkinstalldirs"