Taylor R Campbell [Mon, 9 May 2011 21:30:19 +0000 (21:30 +0000)]
Permit `--constant 0'.
The band loader figures out the size of the constant space anyway.
Is there ever any reason to use the `--constant' option at all?
Taylor R Campbell [Mon, 9 May 2011 04:14:09 +0000 (04:14 +0000)]
Prefer (NOT (PAIR? ...)) over (NULL? ...) in unxpth.scm.
Taylor R Campbell [Mon, 9 May 2011 04:05:50 +0000 (04:05 +0000)]
Permit consecutive slashes in Unix namestrings.
POSIX sez it's kosher:
<http://pubs.opengroup.org/onlinepubs/
9699919799/basedefs/V1_chap03.html#tag_03_266>
I don't know any Unix that treats two leading slashes differently, so
I won't reject that case. However, maybe the pathname abstraction
needs to handle it differently if there are such Unices.
Chris Hanson [Mon, 2 May 2011 05:35:23 +0000 (22:35 -0700)]
Don't run build-ffis.
Chris Hanson [Mon, 2 May 2011 03:52:10 +0000 (20:52 -0700)]
Missed a copyright.
Chris Hanson [Mon, 2 May 2011 03:51:49 +0000 (20:51 -0700)]
Update version number.
Chris Hanson [Mon, 2 May 2011 01:56:20 +0000 (18:56 -0700)]
Update copyright years.
Chris Hanson [Mon, 2 May 2011 01:49:41 +0000 (18:49 -0700)]
Update version number.
Chris Hanson [Mon, 2 May 2011 01:49:02 +0000 (18:49 -0700)]
Update version number.
Chris Hanson [Mon, 2 May 2011 01:46:03 +0000 (18:46 -0700)]
Update version number.
Chris Hanson [Mon, 2 May 2011 01:43:20 +0000 (18:43 -0700)]
Initial revision: imported from cph's private sources.
Chris Hanson [Sun, 1 May 2011 23:37:37 +0000 (16:37 -0700)]
Add patterns for ffi documentation.
Chris Hanson [Sun, 1 May 2011 09:07:36 +0000 (02:07 -0700)]
Don't run "build-ffis"; this rule is broken on Mac OS X.
Chris Hanson [Sun, 1 May 2011 09:03:47 +0000 (02:03 -0700)]
Revert misguided change.
Taylor R Campbell [Sat, 30 Apr 2011 19:44:58 +0000 (19:44 +0000)]
Fix configure with host Scheme check disabled.
Taylor R Campbell [Sat, 30 Apr 2011 19:25:11 +0000 (19:25 +0000)]
Merge branch 'master' of ssh://git.sv.gnu.org/srv/git/mit-scheme
Taylor R Campbell [Sat, 30 Apr 2011 19:20:53 +0000 (19:20 +0000)]
Tighten host Scheme detection in configure script.
Now the script requires MIT_SCHEME_EXE to work if it is set, in order
to detect early the legitimate error of setting it wrong.
Matt Birkholz [Sat, 30 Apr 2011 18:20:19 +0000 (11:20 -0700)]
Oops, remove ALL "debugging printfs".
Matt Birkholz [Sat, 30 Apr 2011 17:43:16 +0000 (10:43 -0700)]
Added compile-time 'imports option to compile-system.
Matt Birkholz [Sat, 30 Apr 2011 17:41:28 +0000 (10:41 -0700)]
Cut out the SHELL middleman; use run-synchronous-subprocess.
Matt Birkholz [Sat, 30 Apr 2011 17:40:09 +0000 (10:40 -0700)]
Un-distinguish LDFLAGS et al for shims or modules.
Taylor R Campbell [Sat, 30 Apr 2011 15:37:15 +0000 (15:37 +0000)]
Suppress host Scheme test by default only if lib/all.com exists.
Taylor R Campbell [Sat, 30 Apr 2011 15:36:28 +0000 (15:36 +0000)]
Make configure fail if create-makefiles or compiler/configure fails.
Taylor R Campbell [Sat, 30 Apr 2011 15:30:20 +0000 (15:30 +0000)]
Reflect autoconf invocation in Setup.sh's output.
Taylor R Campbell [Thu, 28 Apr 2011 22:11:02 +0000 (22:11 +0000)]
Update terminal drawing operation costs on resize.
Fixes random errors during redraw after expanding your terminal.
Evidently nobody uses Edwin in a terminal, at least since I broke
this five years ago...
Taylor R Campbell [Thu, 28 Apr 2011 14:34:18 +0000 (14:34 +0000)]
Omit unreferenced GEN-DELIMS in url.scm.
Taylor R Campbell [Thu, 28 Apr 2011 05:37:04 +0000 (05:37 +0000)]
Check whether requested memory size fits in object datum.
Do this before even trying to allocate the memory.
Taylor R Campbell [Wed, 27 Apr 2011 21:16:04 +0000 (21:16 +0000)]
Fix some header files in the FFI.
Taylor R Campbell [Wed, 27 Apr 2011 21:14:55 +0000 (21:14 +0000)]
Avoid GNUism $^ in makefiles.
Taylor R Campbell [Wed, 27 Apr 2011 20:39:07 +0000 (20:39 +0000)]
Omit unreferenced variable in COMPILE-SYSTEM.
Taylor R Campbell [Wed, 27 Apr 2011 20:30:47 +0000 (20:30 +0000)]
Simplify PARSE-PACKAGE-EXPRESSIONS with FILTER-MAP.
Taylor R Campbell [Wed, 27 Apr 2011 19:23:38 +0000 (19:23 +0000)]
Merge branch 'master' of ssh://git.sv.gnu.org/srv/git/mit-scheme
Matt Birkholz [Tue, 26 Apr 2011 20:09:24 +0000 (13:09 -0700)]
Oops, for-all?'s arguments are "backward".
Matt Birkholz [Tue, 26 Apr 2011 17:48:28 +0000 (10:48 -0700)]
Turned off c-include-noisily? by default.
Turned it on in the FFI generator. Use it to suppress the "Loading
gtk-types.bin..." notifications when compiling files that c-include.
Matt Birkholz [Tue, 26 Apr 2011 17:47:42 +0000 (10:47 -0700)]
Fixed compile-ffi to use run-shell-command.
Now sets the working directory and checks make's exit code.
Matt Birkholz [Tue, 26 Apr 2011 17:42:52 +0000 (10:42 -0700)]
Ignore unknown options/descriptions in .pkg files.
Matt Birkholz [Mon, 25 Apr 2011 20:39:50 +0000 (13:39 -0700)]
Removed redundant --preserve-timestamps.
Matt Birkholz [Mon, 25 Apr 2011 20:00:09 +0000 (13:00 -0700)]
Fixed recent enhancement to compile-file.
Matt Birkholz [Wed, 20 Apr 2011 15:26:08 +0000 (08:26 -0700)]
Fix compile-system to load into the correct environment.
Matt Birkholz [Tue, 19 Apr 2011 07:49:14 +0000 (00:49 -0700)]
New compile-system procedure. Replaced ffi.sf and ffi.cbf.
* src/compiler/base/toplev.scm (compile-file): Only declare
integrate-external when dependencies have no type. Thus a dependency
on e.g. "gtk-const.bin" might cause the dependent file to be
re-compiled without a spurious warning about a missing .ext file.
* src/cref/: butils.scm, cref.pkg: Added new file butils.scm,
containing a compile-system procedure that applies compile-file to
each file mentioned in a .pkg file.
* src/ffi/: compile.scm, ffi.cbf, ffi.sf: Replaced the old .cbf and
.sf files with a new, modern compile.scm file.
Matt Birkholz [Mon, 18 Apr 2011 15:25:25 +0000 (08:25 -0700)]
Fixed ffi/Makefile-fragment install target.
* src/Setup.sh: Create src/lib/ links to the ffi-test FFI.
* src/ffi/Makefile-fragment: Punt installing the ffi-test FFI, which
is intended for `make check', which developers run in the source tree.
The links in src/lib/ are enough; no need to copy files there.
Taylor R Campbell [Mon, 18 Apr 2011 02:33:51 +0000 (02:33 +0000)]
Merge branch 'master' of ssh://git.sv.gnu.org/srv/git/mit-scheme
Matt Birkholz [Mon, 18 Apr 2011 00:08:38 +0000 (17:08 -0700)]
Added FFI test.
* doc/ffi/ffi.texinfo: Punt the Makefile fragments for the example,
and the logic behind the leak-proof malloc/free procedures.
* doc/user-manual/user.texinfo: Needlessly picked some consistency nits.
* src/Clean.sh, src/Setup.sh: Link config.sub and config.guess to
microcode/*, and clean them too. These scripts are used by
src/configure.ac, which uses AC_CANONICAL_HOST to configure the
compilation and linking of FFIs.
* src/Makefile.in (FFIS, build-ffis): Added FFIS, the list of
configured foreign library interfaces (subdirs). These are built by
the new build-ffis target, which follows build-bands in most places,
and does `make build' in each ffi subdir.
* src/configure.ac: Added --enable-debugging, FFIS, CCLD, DEFS,
CFLAGS, CPPFLAGS, LDFLAGS, SHIM_CFLAGS and SHIM_LDFLAGS. Include
microcode/achost.ac. Added FFIS to the bundles list.
* src/etc/compile.scm (compile-ffi): New. This procedure arranges to
compile an FFI subdir as a LIARC bundle when LIARC is in use.
* src/etc/functions.sh (maybe_rm): Remove symlinks too.
* src/etc/make-liarc.sh: Added build-ffis after build-bands.
* src/etc/std-makefile-prefix: Added CC, CCLD, DEFS, CFLAGS, CPPFLAGS,
LDFLAGS, COMPILE, LINK, SHIM_CFLAGS, SHIM_LDFLAGS, COMPILE_SHIM and
LINK_SHIM, useful when building a foreign library interface shim.
* src/ffi/.gitignore: Ignore ffi-test-* build products.
* src/ffi/Clean.sh: Punt prhello example. Clean up ffi-test-* build
products.
* src/ffi/Makefile-fragment: Punt prhello example. Build and install
an FFI test lib instead.
* src/ffi/: ffi-test.c.stay, ffi-test.cdecl, ffi-test.h: The new test
foreign library and interface.
* src/ffi/: prhello.cdecl, prhello.scm: Removed. Now in doc/;
replaced in src/ by ffi-test*.*.
* src/microcode/: achost.ac, configure.ac: Moved the host
configuration from configure.ac to the new achost.ac, to share with
src/configure.ac.
* src/runtime/ffi.scm (guarantee-alien, error:not-alien): Use the
standard arglist (object operator), not (operator object #!optional
ctype), and do not loop insisting on a qualifying object. Integrate
the test, separated from the restart code, which goes in the new,
global error:not-alien procedure.
(guarantee-alien-function, error:not-alien-function): New, like
guarantee-alien and error:not-alien. Use them in call-alien.
(make-alien-to-free): New, for interfacing to C functions like
malloc() that return something that needs to be freed with free().
Use it in the Scheme malloc procedure, and the test FFI.
* src/runtime/runtime.pkg: Added error:not-alien,
guarantee-alien-function, error:not-alien-function and
make-alien-to-free.
* tests/Clean.sh: New, for cleaning up after tests.
* tests/check.scm: Added tests/ffi/test-ffi.scm. Hacked handling of
test-flonum-casts.com so that `make check' works on portable C.
* tests/ffi/test-ffi-wrapper.scm: New. Code that needs to be
syntaxed/compiled as part of the FFI test.
* tests/ffi/test-ffi.scm: New. A test of the C/Unix FFI.
Taylor R Campbell [Sat, 16 Apr 2011 00:40:37 +0000 (00:40 +0000)]
Run Scheme in batch mode in the scripts in src/etc/.
Taylor R Campbell [Sat, 16 Apr 2011 00:25:41 +0000 (00:25 +0000)]
Make `--batch-mode' without `--interactive' imply non-interactive.
In this case, don't check whether stdin/stdout/stderr are ttys to
determine whether we are interactive.
This keeps `scheme --batch-mode' from futzing with the tty interrupt
characters, so that if you run it from a script, there is no window
during which ^G becomes the terminal's interrupt character and ^C its
quit character. E.g., if you have set `stty intr ^C', then Scheme
won't interfere with that while you run your script.
Taylor R Campbell [Sun, 10 Apr 2011 21:17:29 +0000 (21:17 +0000)]
Use do { ... } while (0) for command macros in uxproc.c.
Omit needless curly braces in subprocess_death.
Taylor R Campbell [Sun, 10 Apr 2011 19:34:53 +0000 (19:34 +0000)]
Check for tcsetpgrp failure.
Taylor R Campbell [Sun, 10 Apr 2011 19:31:52 +0000 (19:31 +0000)]
Don't fflush stdout and stderr before forking.
Not necessary; the child will never use them before exec'ing.
The simpler this whole mess can be made, the better...
Taylor R Campbell [Sun, 10 Apr 2011 19:24:31 +0000 (19:24 +0000)]
Minor cosmetic changes to uxproc.c.
Taylor R Campbell [Sun, 10 Apr 2011 19:21:06 +0000 (19:21 +0000)]
Use the closefrom system call if available to close all fds.
If not available, fall back to fcntl(F_CLOSEM); if that's not
available, fall back to closing all fds up to and including
fcntl(F_MAXFD); if that's not available, fall back to closing all
fds below UX_SC_OPEN_MAX like before.
Each case tested under NetBSD by running runtime/test-process.scm,
evaluating (RUN-SHELL-COMMAND "ls"), and ktracing Scheme during
(RUN-SUBPROCESS-IN-FOREGROUND "/usr/bin/true" '#("true") '#())
with `ktrace -d -i' to make sure that it uses the right sequence of
system calls.
Taylor R Campbell [Sun, 10 Apr 2011 19:04:50 +0000 (19:04 +0000)]
When spawning subprocesses, handle the setpgid race more gracefully.
Taylor R Campbell [Sun, 10 Apr 2011 05:03:06 +0000 (05:03 +0000)]
Add some disparaging comments about my code...yechhh.
Taylor R Campbell [Sun, 10 Apr 2011 05:01:51 +0000 (05:01 +0000)]
Pre-compile the regexps in IMAIL-SUMMARY-MATCH-LINE.
This slightly reduces some of the constant factors in the O(n)-time
(!) operation to expand summary buffers...
Taylor R Campbell [Sat, 9 Apr 2011 23:46:01 +0000 (23:46 +0000)]
Ignore some variables in test-floenv.scm.
Taylor R Campbell [Sat, 9 Apr 2011 22:17:38 +0000 (22:17 +0000)]
Ignore variable I in MAKE-RANDOM-SVL in character set tests.
Taylor R Campbell [Sat, 9 Apr 2011 22:00:26 +0000 (22:00 +0000)]
Fix environment for runtime/test-wttree in tests/check.scm.
Taylor R Campbell [Sat, 9 Apr 2011 21:46:34 +0000 (21:46 +0000)]
Implement `make check' in the top-level makefile.
The implementation is totally kludgey, and the tests take an
unreasonably long time to run (since we've mixed stress tests with
simple tests), but this is better than nothing, and may help to
complement firing up Edwin as the general way to test Scheme.
Taylor R Campbell [Sat, 9 Apr 2011 21:25:55 +0000 (21:25 +0000)]
Refactor microcode/test-flonum-casts.scm into lots of little tests.
Taylor R Campbell [Wed, 6 Apr 2011 02:55:11 +0000 (02:55 +0000)]
Work around brain damage in Linux's madvise.
Taylor R Campbell [Tue, 5 Apr 2011 01:02:32 +0000 (01:02 +0000)]
Fix diagram of memory in memmag.c to reflect Microcode 15.
Taylor R Campbell [Tue, 5 Apr 2011 00:52:36 +0000 (00:52 +0000)]
Add comment about (not) dynamically scoping madvice.
Taylor R Campbell [Tue, 5 Apr 2011 00:33:40 +0000 (00:33 +0000)]
Advise operating system about memory access during GC.
- Expect sequential access to oldspace during gc_scan_oldspace.
- Free heap pages (newspace) before copying tospace over them.
- Free tospace pages after saving tospace.
The OS hooks are implemented only for Unix, in terms of posix_madvise
and madvise. Implementing them for Windows and/or OS/2 is left as an
exercise for the reader.
Taylor R Campbell [Sun, 3 Apr 2011 21:14:59 +0000 (21:14 +0000)]
Use a (hidden) top-level variable for tag in structure predicates.
This allows the predicates to be usefully integrated.
Integrating the predicate and guarantor, and ignoring reference traps
to the tag, measurably improves performance at least of contrived
programs.
Taylor R Campbell [Sun, 3 Apr 2011 17:48:50 +0000 (17:48 +0000)]
Back out recent misguided changes.
It turns out dynamic scope and vi don't work very well.
This also fixes a grammatical error reported to Arthur by an angry
centurion.
Arthur A. Gleckler [Sun, 3 Apr 2011 06:56:59 +0000 (23:56 -0700)]
Fixed bug that caused (load-option 'xml) to fail with this error
message:
;The object #[uri 11 ""], passed as an argument to make-xml-name, is not in the correct range.
The bug was caused by the fix to `->absolute-uri' in change
562020fdf80823b5825ad901e208b10a4d3b058b.
Taylor R Campbell [Fri, 1 Apr 2011 15:11:23 +0000 (15:11 +0000)]
Fix typo in termination message.
Taylor R Campbell [Fri, 1 Apr 2011 15:05:28 +0000 (15:05 +0000)]
Change Edwin's default key bindings to match vi conventions.
All the world is Unix (except for the small irrelevant part in
Redmond that's VMS), so this should improve Edwin's widespread
adoption.
Taylor R Campbell [Fri, 1 Apr 2011 14:30:55 +0000 (14:30 +0000)]
Switch to dynamic scope by default.
Taylor R Campbell [Tue, 29 Mar 2011 00:57:38 +0000 (00:57 +0000)]
Merge branch 'master' of ssh://git.sv.gnu.org/srv/git/mit-scheme
Joe Marshall [Mon, 28 Mar 2011 17:41:18 +0000 (10:41 -0700)]
Add and export GUARANTEE-PROMISE.
Joe Marshall [Thu, 24 Mar 2011 20:48:13 +0000 (13:48 -0700)]
Add numerator->exact and denominator->exact.
Taylor R Campbell [Wed, 23 Mar 2011 04:34:00 +0000 (04:34 +0000)]
When signalling a file open error, read channel type before closing.
Chris Hanson [Sun, 20 Mar 2011 09:26:07 +0000 (02:26 -0700)]
Copy example files to doc/ffi/ directory to avoid relative paths,
which aren't working on my machine.
Chris Hanson [Sun, 20 Mar 2011 09:25:59 +0000 (02:25 -0700)]
Bump version number and current year.
Chris Hanson [Sun, 20 Mar 2011 09:25:38 +0000 (02:25 -0700)]
For some reason, fatal_buf doesn't have a NUL under certain circumstances on my Mac. Instead of calling strlen, do a more careful scan that stops at the end of the buffer.
Chris Hanson [Sun, 20 Mar 2011 05:59:34 +0000 (22:59 -0700)]
Bump version number and current year.
Chris Hanson [Sun, 20 Mar 2011 05:57:05 +0000 (22:57 -0700)]
Update copyright dates in reference headers.
Joe Marshall [Wed, 9 Mar 2011 18:27:42 +0000 (10:27 -0800)]
Add GUARANTEEs for positive, negative, non-positive, and non-negative numbers.
Taylor R Campbell [Sat, 26 Feb 2011 15:13:02 +0000 (15:13 +0000)]
Merge branch 'master' of ssh://git.sv.gnu.org/srv/git/mit-scheme
Joe Marshall [Fri, 25 Feb 2011 20:58:30 +0000 (12:58 -0800)]
Export some predicates.
Taylor R Campbell [Thu, 17 Feb 2011 20:51:56 +0000 (20:51 +0000)]
Fix typo in `mail-relay-service' documentation string.
Taylor R Campbell [Mon, 14 Feb 2011 18:51:08 +0000 (18:51 +0000)]
New (Unix) primitive CHANNEL-FILE-ATTRIBUTES for fstat.
Also, I meant `eastern hemisphere' in the previous commit, unless the
earth's magnetic field has just reversed again...no, wait...
Taylor R Campbell [Mon, 14 Feb 2011 17:39:45 +0000 (17:39 +0000)]
Fix ENCODE-TIME to correctly handle negative time zones.
This bug has been lying here for fifteen years. Obviously we need
more MIT Scheme hackers in the western hemisphere...
All this time and date code desperately needs a lot of automatic
tests, too.
Taylor R Campbell [Tue, 8 Feb 2011 01:19:01 +0000 (01:19 +0000)]
Bump microcode version number.
New primitive NANOTIME-SINCE-UTC-EPOCH, and a bajillion others.
Taylor R Campbell [Mon, 7 Feb 2011 21:49:52 +0000 (21:49 +0000)]
New primitive NANOTIME-SINCE-UTC-EPOCH.
This returns the number of seconds, with at most nanosecond
resolution, that have elapsed since the start of 1972 in UTC.
Representation is fixed-point, stored in a pair given as input.
See the comments in uxenv.c for more details.
Taylor R Campbell [Mon, 24 Jan 2011 14:43:42 +0000 (14:43 +0000)]
Two minor cosmetic changes to runtime/wttree.scm.
Taylor R Campbell [Mon, 24 Jan 2011 14:26:36 +0000 (14:26 +0000)]
Fix wt-tree balancing. Add some trivial tests.
Thanks to Yoichi Hirai and Kazuhiko Yamamoto for analyzing the nature
of the bug and finding a good fix.
The trivial tests are enough to catch trivial errors, and one
manifestation of the balancing bug, but they should be replaced by a
more comprehensive test suite later.
Taylor R Campbell [Sat, 15 Jan 2011 04:36:39 +0000 (04:36 +0000)]
Check URI record arguments more carefully in ->MUMBLE-URI.
->ABSOLUTE-URI would formerly accept URI records representing
relative references, even though it would reject their string
representations. Now it rejects both.
Taylor R Campbell [Tue, 4 Jan 2011 03:35:38 +0000 (03:35 +0000)]
Look in /usr/local/share/info for Info files in Edwin by default.
This is where the doc/ makefile actually installs them by default.
Chris Hanson [Fri, 24 Dec 2010 04:57:35 +0000 (20:57 -0800)]
Merge branch 'master' of git.sv.gnu.org:/srv/git/mit-scheme
Chris Hanson [Fri, 24 Dec 2010 04:37:31 +0000 (20:37 -0800)]
Fix floenv issues with MacOSX.
Matt Birkholz [Tue, 21 Dec 2010 17:28:03 +0000 (10:28 -0700)]
FFI support for 64bit architectures.
* src/ffi/generator.scm: Declare long callback IDs, large enough to
avoid truncation warnings when the toolkit type is also large. Use
%ld instead of %d for sizeof and member offsets, and cast them to
long. On x86_64, these have types ulong and long respectively.
* src/microcode/: pruxffi.c, pruxffi.h: (callback_run_kernel)
(callback_run_handler): Declare long callback_id params. Use %ld.
* src/runtime/ffi.scm (radix): Parameterize alien operations to
support 64bit or 32bit addresses.
Joe Marshall [Sat, 18 Dec 2010 01:32:08 +0000 (17:32 -0800)]
Fix tag table entry for flonum for 64-bit platforms.
Joe Marshall [Fri, 17 Dec 2010 23:31:36 +0000 (15:31 -0800)]
Fix copying of ACCESS.
Taylor R Campbell [Fri, 10 Dec 2010 06:46:35 +0000 (06:46 +0000)]
Fix STRIP-SUBJECT-RE on "Re: ".
Taylor R Campbell [Tue, 7 Dec 2010 23:37:59 +0000 (23:37 +0000)]
Fix datime.scm's time formats to accept up to 61 seconds in a minute.
Minutes in any UTC-based time system, which covers every system of
which representations are parsed in datime.scm, can have 59, 60, or
61 seconds; previously we refused to parse representations of the
61st second.
Unfortunately, our notion of `universal time' is still essentially
Common Lisp's ill-specified notion of universal time, and implemented
by POSIX's mind-bogglingly brain-damaged notion of `number of seconds
since the Epoch' which actually means `number of seconds since the
Epoch, minus the number of them that were leap seconds in UTC'.
Taylor R Campbell [Tue, 30 Nov 2010 19:16:08 +0000 (19:16 +0000)]
Fix silly thinko in definition of STRIP-SUBJECT-RE.
Also omit needless unsafe fixnum specialization.
Taylor R Campbell [Wed, 24 Nov 2010 18:29:14 +0000 (18:29 +0000)]
Handle EINTR from opendir.
Taylor R Campbell [Fri, 19 Nov 2010 18:54:11 +0000 (18:54 +0000)]
Fix comment about euclidean division -- r may be zero.
Taylor R Campbell [Fri, 19 Nov 2010 07:24:54 +0000 (07:24 +0000)]
Work around bug in glibc's fegetenv on amd64.