Add the `%host-type' global variable.

* configure.ac: Define `HOST_TYPE'.

* libguile/load.c (sys_host_type): New variable.

* doc/ref/api-options.texi (Build Config): Document `%host-type'.

configure.ac

@@ -86,6 +86,9 @@ AM_CONDITIONAL(HAVE_MAKEINFO, test "$have_makeinfo" = yes)
 
 AM_PATH_LISPDIR
 
+AC_DEFINE_UNQUOTED([HOST_TYPE], ["$host"],
+  [Define to the host's GNU triplet.])
+
 #--------------------------------------------------------------------
 #
 # User options (after above tests that may set default CFLAGS etc.)

doc/ref/api-options.texi

@@ -1,6 +1,6 @@
 @c -*-texinfo-*-
 @c This is part of the GNU Guile Reference Manual.
-@c Copyright (C)  1996, 1997, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2008
+@c Copyright (C)  1996, 1997, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2008, 2009
 @c   Free Software Foundation, Inc.
 @c See the file guile.texi for copying conditions.
 
@@ -178,6 +178,14 @@ libguile/libpath.h, which is completely generated, so deleting this file
 before a build guarantees up-to-date values for that build.
 @end defvar
 
+@cindex GNU triplet
+@cindex canonical host type
+
+@defvar %host-type
+The canonical host type (GNU triplet) of the host Guile was configured
+for, e.g., @code{"x86_64-unknown-linux-gnu"} (@pxref{Canonicalizing,,,
+autoconf, The GNU Autoconf Manual}).
+@end defvar
 
 @node Feature Tracking
 @subsection Feature Tracking

libguile/load.c

@@ -778,6 +778,10 @@ scm_c_primitive_load_path (const char *filename)
 
 /* Information about the build environment.  */
 
+SCM_VARIABLE_INIT (sys_host_type, "%host-type",
+		   scm_from_locale_string (HOST_TYPE));
+
+
 /* Initialize the scheme variable %guile-build-info, based on data
    provided by the Makefile, via libpath.h.  */
 static void