* module/system/base/target.scm (%target-endianness, %target-word-size):
New fluids.
(%native-word-size): New variable.
(with-target): Set these fluids.
(cpu-endianness, cpu-word-size, triplet-cpu, triplet-vendor,
triplet-os): New procedures.
(target-cpu, target-vendor, target-os): Use them.
(target-endianness, target-word-size): Refer to the corresponding
fluid.
* libguile/objcodes.c (target_endianness_var, target_word_size_var): New
global variables.
(NATIVE_ENDIANNESS): New macro.
(target_endianness, target_word_size, to_native_order): New functions.
(make_objcode_from_file): Use `scm_bytecode_to_native_objcode' instead
of `scm_bytecode_to_objcode'.
(bytecode_to_objcode): New function, based on `scm_bytecode_to_objcode',
with the addition of an `endianness' and `word_size' parameters.
(scm_bytecode_to_objcode): Use it.
(scm_bytecode_to_native_objcode): New function.
(scm_write_objcode): Use `target_word_size' and `target_endianness'.
Convert OBJCODE's len and meta-len to native byte order.
(scm_init_objcodes): Initialize `target_endianness_var' and
`target_word_size_var'.
* libguile/objcodes.h (scm_bytecode_to_native_objcode): New declaration.
* libguile/vm.c (really_make_boot_program): Use
`scm_bytecode_to_native_objcode' instead of `scm_bytecode_to_objcode'.
* test-suite/tests/asm-to-bytecode.test (%objcode-cookie-size): New
variable.
(test-target): New procedure.
("cross-compilation"): Add `test-target' calls and the "unknown
target" test.
* module/system/base/target.scm (validate-target): Accept any tuple with
at least 3 parts.
* test-suite/tests/asm-to-bytecode.test (test-triplet): New procedure.
("cross-compilation"): New test prefix.
* module/Makefile.am:
* module/system/base/target.scm: Add a minimal module to parameterize
the target system type and inspect properties on it like cpu, vendor,
os, endianness, and word size.
