Rework configure logic wrt GNU autotools

Rather than requiring them of a certain version, detect if they are present
(and have sufficient version) and select an appropriate companion tool
otherwise. The reason is that, for example, most recent gettext requires
automake 1.15, but the newest available CentOS has 1.13. Hence, the option
to "upgrade your system" does not apply, and the warning comment above
the companion tools is rather scary.

With this approach, it will work out of the box - either by using the host's
tools, or by building them as needed. Note that the user can still change
the setting in the config.

While there, propagate the new version checking macro to awk/bash/host binutils,
and switch from --with-foo=xxx to officially blessed FOO=xxx: the latter
does not require checking for bogus values (i.e., --with-foo, --without-foo)
and AC_PROG_* macros recognize the corresponding settings without further
modifications. For now, I kept --with-foo=, if only to complain and steer
people to the new way. To be cleaned up after a release.

Signed-off-by: Alexey Neyman <stilor@att.net>

Makefile.in

@@ -57,8 +57,8 @@ export docdir          := @docdir@@subdocdir@
 export mandir          := @mandir@
 export datarootdir     := @datarootdir@
 export install         := @INSTALL@
-export bash            := @_BASH@
-export awk             := @_AWK@
+export bash            := @BASH_SHELL@
+export awk             := @AWK@
 export grep            := @GREP@
 export make            := @MAKE@
 export sed             := @SED@

config/companion_tools.in

@@ -2,28 +2,6 @@
 
 menu "Companion tools"
 
-config COMP_TOOLS_FORCE_make_3_81
-    def_bool y
-    depends on ! CONFIGURE_has_make_3_81_or_newer
-    select COMP_TOOLS
-    select COMP_TOOLS_make
-
-comment "READ HELP before you say 'Y' below !!!"
-
-config COMP_TOOLS
-    bool
-    prompt "Build some companion tools"
-    help
-      Crosstool-NG relies on some external tools to be recent enough, namely:
-        make >= 3.81
-        m4 >= 1.4.12
-        autoconf >= 2.63
-        automake >= 1.10.2
-        libtool >= 2.2.4
-
-      If your system has older versions, we can build them for you,
-      but you are strongly encouraged to update your system instead!
-
 config COMP_TOOLS_FOR_HOST
     bool
     prompt "Install companion tools for host"
@@ -32,8 +10,6 @@ config COMP_TOOLS_FOR_HOST
       tools into the final toolchain (rather than just using them
       to build it).
 
-if COMP_TOOLS || COMP_TOOLS_FOR_HOST
 source "config.gen/companion_tools.in"
-endif
 
 endmenu

config/companion_tools/autoconf.in

@@ -1,5 +1,7 @@
 # Autoconf
 
+## default y if !CONFIGURE_has_autoconf_2_63_or_newer
+## default y if !CONFIGURE_has_autoreconf_2_63_or_newer
 ## help Autoconf
 
 choice
@@ -14,7 +16,8 @@ config AUTOCONF_V_2_69
 
 config AUTOCONF_V_2_65
     bool
-    prompt "2.65"
+    prompt "2.65 (OBSOLETE)"
+    depends on OBSOLETE
 
 endchoice
 

config/companion_tools/automake.in

@@ -1,5 +1,6 @@
 # Automake
 
+## default y if !CONFIGURE_has_automake_1_15_or_newer
 ## help Automake
 
 choice

config/companion_tools/libtool.in

@@ -1,5 +1,7 @@
 # Libtool
 
+## default y if !CONFIGURE_has_libtool_2_4_or_newer
+## default y if !CONFIGURE_has_libtoolize_2_4_or_newer
 ## help Libtool
 
 choice

config/companion_tools/m4.in

@@ -1,5 +1,6 @@
 # GNU m4
 
+## default y if !CONFIGURE_has_gnu_m4_1_4_12_or_newer
 ## help GNU m4
 
 choice

config/companion_tools/make.in

@@ -1,5 +1,6 @@
 # GNU make
 
+## default y if !CONFIGURE_has_make_3_81_or_newer
 ## help GNU make
 
 choice