Port to Solaris 'make' and use a Posixish shell on Solaris.

Port to Solaris 'make' and use a Posixish shell on Solaris.

* bootstrap.conf (gnulib_modules): Add gnu-make, posix-shell.
* build-aux/check.mk (SHELL): Set to $(PREFERABLY_POSIX_SHELL),
so that commands can assume Posix syntax.
(ENABLE_HARD_ERRORS, TEST_LOGS): Don't use GNU Make's "?=" syntax.
(SH_E_WORKAROUND): New macro.
(am__check_pre, $(TEST_SUITE_LOG)): Use it.
(am__check_pre): Fail if "mkdir" fails.  Use $(SHELL)
rather than relying on the "#!/bin/sh" in the file, so that tests
can use Posix syntax.
(am__check_pre, am__tty_colors): Use $$src rather than $$<, to
support the Posix-make $(TEST_LOGS) rule.
(%.log: %.test, %.log: %$(EXEEXT)): Remove unused inference rules
that rely on a GNU Make extension and cause Solaris 'make' to fail.
(SUFFIXES): New macro, so that we can use Posix style inference rules.
(%.log: %): Use this rule only if GNU_MAKE.
Set $$src so that macros can use $$src rather than $$<.
(CHECK-FORCE, DEPENDENCY, $(TEST_LOGS)): New macros and rules,
which rely only on Posix 'make' semantics, and are used only with
non-GNU 'make' implementations.  $(TEST_LOGS) invokes 'make'
recursively (and a bit inefficiently) to simulate the GNU 'make'
rules.
(.log.html): Renamed from "%.html: %.log", so that it relies only
on Posix 'make' semantics.
(check-clean, .PHONY): Do not depend on check-clean-local, since
Solaris 'make' complains about nonexistent rules like that.
* src/Makefile.am (SUFFIXES): Remove; no longer needed.
(groups): Use a specific rule rather than an inference rule that
is only instantiated once.  The inference-rule approach does not
work with Solaris 'make', which gets confused by the "groups:
Makefile" line.  It's not clear from the Posix spec that Solaris
'make' is buggy here, so instead of worrying about it, rewrite
the makefile so that it clearly conforms to Posix.
* tests/check.mk (TESTS_ENVIRONMENT): Export PACKAGE_BUGREPORT.
GNU 'make' does this automatically for us, but Solaris 'make'
doesn't.

2007-11-15  Paul Eggert  <eggert@cs.ucla.edu>