at the top ofltconfig.in is ugly, but will go away when the rest
of ltconfig is migrated.
* Makefile.am (libtool): Pass the value of $ECHO to ltconfig as
an environment variable.
* libtool.m4 (_LT_AC_PROG_ECHO_BACKSLASH): Quote the ECHO value
correctly so that it inserts the correct code into configure.in
suitably quoted for M4 expansion. This code needs to be near
the top of configure.in as it calls itself recursively, so I
am using AC_DIVERSION_NOTICE (or simply NOTICE on CVS
Autoconf). The value of ECHO is also substitued into the
Makefile to be used when Make calls ltconfig to generate
libtool, so another layer of quotation is required for the
Makefile.
(AC_LIBTOOL_SETUP): Use it.
* ltconfig.in: Accept a value for ECHO from the environment, and
carefully substitue for $0 if it is present in the ECHO value.
Because ECHO was quoted for Make, when ltconfig is called by
configure, it is overquoted, and one layer of quotes must be
stripped.
interdependent libraries (e.g. -la -lb -la),
this requires adding deplibs in reverse order
* ltmain.in: link dlpreopened libraries before other libraries
(reported by Pavel Roskin)
* mdemo/Makefile.am: build and link libsub.la
* mdemo/sub.c: new file used by both dlopened modules
* mdemo/foo*: use sub() defined in libsub
* tests/dryrun.test: build libsub.la
* mdemo/Makefile.am: always link mdemo.static with -static
* mdemo/configure.in: ditto
* ltmain.in: fix dlopen/dlpreopening of objects
* ltmain.in (ILD): fix misplaced `continue' in -R* argument handler
* ltmain.in: merge duplicated code of clean and uninstall mode
* libtool.m4: recognize powerpc*linux* (reported by
Dirk A. Mueller <dmuell@gmx.net>)
AC_SUBST, `AC_SUBST(FILE)' can never work. Use MAGIC as the
holder of the command to run in file_magic_cmd instead.
* ltconfig.in: s/FILE/MAGIC/g.
* libtool.m4 (AC_PROG_LIBTOOL): set MAGIC in the environment when
calling ltconfig.
(AC_PATH_MAGIC): renamed from AC_PATH_FILE.
(AC_PATH_TOOL_PREFIX): s/FILE/MAGIC/g. Also set file_magic_cmd
to '${MAGIC}' so that make can grok it.
* Makefile.am (libtool):
(clibtool): ditto.
* ltconfig.in: replace $objdir with $output_objdir
* ltmain.in: change to the builddir before relinking programs
* ltmain.in, ltconfig.in, libtool.m4, ltdl.m4:
remove unnessary spaces from line endings
programs, libraries and objects, allow linking of shared libraries
against static libraries/objects on platforms that support it
but print a warning, fix some typos
* partially revert my previous change and
update only copyright notices of files that were actually modified
* NEWS: update
* libltdl/Makefile.am: version number was wrong
* libltdl/ltdl.c (tryall_dlopen): revert Gary's change
since it breaks dlpreopening
* ltdl.m4: ditto
* libltdl/ltdl.c (sys_search_path): search in the system default
library search path, too
* ltdl.m4 (AC_LTDL_SYSSEARCHPATH): extract the path
* libltdl/ltdl.c (find_module): remove bogus file_not_found_error
* libltdl/ltdl.c (load_deplibs): implement loading of dependency
libraries
* libltdl/ltdl.c (unload_deplibs): implement unloading of dependency
libraries
* libltdl/ltdl.c (lt_dlexit): correctly close all modules and
their dependencies
* libltdl/ltdl.c (lt_dlforeach): new function
* libltdl/ltdl.h: ditto
* doc/libtool.texi (using libltdl): document it
* libtool.m4: reformatting, only add -I$topsrc_dir/libltdl to
INCLTDL
* libtoolize.in: reformatting
* ltconfig.in: reformatting
* ltmain.in: reformatting
* mdemo/configure.in: AC_SUBST INCLTDL
* mdemo/Makefile.am: use INCLTDL
* tests/Makefile.am: reexport OBJEXT and EXEEXT
* tests/dryrun.test: use them for building main.obj and mdemo.exe
was set to the opposite of what it should be.
* configure.in (AC_LIBTOOL_WIN32_DLL): Call to this macro is
required for libtool configury to test lt_cv_need_dllmain on
Windows.
* doc/libtool.texi (using libltdl): document new lt_dlinfo struct,
replace NULL with @code{NULL}, document lt_dlsetdata(),
lt_dlgetdata() and lt_dlgetinfo()
* libltdl/Makefile.am: increment interface version number
* libltdl/configure.in: set version number to 1.1
* libltdl/ltdl.c: make some variables public by moving them
to the info struct, add support for application specific data
within module handles, new lt_dlsetdata(), lt_dlgetdata() and
lt_dlgetinfo() functions,
fix memory leaks, minor cleanups
* libltdl/ltdl.h: ditto
* mdemo/main.c: demonstrate use of lt_dlgetinfo,
improved handling of errors
* ltconfig.in: set hardcode_into_libs = yes for GNU/Hurd, Linux
and Solaris, only hardcode *all* run-paths if hardcode_into_libs
is set to 'all', otherwise hardcode only user-specified rpaths
into libraries
* ltmain.in: minor cleanups, we don't need to add user-specified
rpaths to compile_rpath, finalize_rpath is sufficient
* ltconfig.in: transform linux* -> *linux-gnu* _after_ host_os has
been set! (reported by Bruno Haible <haible@ilog.fr>)
* configure.in: AC_SUBST reload_flag, deplibs_check_method
and file_magic_cmd
* README: use 'libtool --version' instead of 'ltconfig --version'
(suggested by Francios Pinard <pinard@iro.umontreal.ca>
* THANKS: added Olly Betts and Pavel Roskin
* doc/libtool.texi: fix typo
* fix major bugs which rendered libtool virtually
unusable (i.e. not portable):
* ltconfig.in: don't hardcode system dependent variables in ltconfig!!
but set sane defaults
* Makefile.am: pass variables from AC_LIBTOOL_SETUP to ltconfig
* libtool.m4: ditto, fix typo in AC_PROG_LD_RELOAD_FLAG
* ltconfig.in: use old_deplibs for archives, too
remove second occurence of sysv5
* ltmain.in: fix typo, fix the second occurence of -DPIC, too
* libltdl/Makefile.am: increment version number, fix typo
* libltdl/ltdl.c (lt_dlsym): don't report an error if the
libltdl-style symbol name wasn't found
* ltconfig.in: add support for Unixware (sysv4.2uw2*)
AC_PATH_TOOL_GREP_OUTPUT.
(AC_PATH_TOOL_PREFIX): new macro replaces
AC_PATH_PROG_GREP_OUTPUT.
(AC_LD_RELOAD_FLAG): migrated from ltconfig.in.
(AC_DEPLIBS_CHECK_METHOD): ditto.
* ltconfig.in (reload_flag): moved to libtool.m4.
(deplbs_check_method): ditto.
more general AC_PATH_PROG_GREP_OUTPUT.
(AC_PATH_TOOL_VERSION_GREP): removed in favour of the more general
AC_PATH_TOOL_GREP_OUTPUT.
(AC_PROG_LIBTOOL): Search for a working find program in the
user's PATH using the new macros.
the value found in libtool.m4 at configure time.
* libtool.m4 (AC_PATH_TOOL_GREP_VERSION): New macro, combines
AC_PATH_PROG and AC_CHECK_TOOL with a test which greps the
output of $ac_dir/${ac_prefix}<tool> --version for a
given regex.
(AC_PATH_PROG_GREP_VERSION): New macro used by the above.
(AC_LIBTOOL_SETUP): Use the new macros to search the PATH
[starting at /usr/bin] for a file program which accepts
--version and has "file" in its --version output.
ltconfig.in.
* ltconfig.in: replaced several of the simple feature tests with
substitutions from config.status.
* Makefile.am (ltconfig): generate ltconfig with config.status.
* configure.in (AC_OUTPUT): generate ltconfig with config.status.
* libtool.m4 (mingw32, AC_LIBTOOL_SETUP): probe for -mdll vs -dll
under cygwin/mingw.
probe whether the cygwin/mingw library supplies a stub DllMain
(but this information isn't yet used).
* ltconfig.in (mingw32, extract_expsyms_cmds): if HOST_CC is set,
use that to build impgen so we can use it when cross-compiling.
use correct entry points for mingw so static C++ constructors get
called for code in the DLL.
* ltmain.in (impgen.c): define O_BINARY to 0 if it is not in the
system headers.
AC_CHECK_TOOL in AC_LIBTOOL_SETUP.
* libtool.m4 (AC_PROG_LIBTOOL): Pass the $build variable to
ltconfig.
(AC_PROG_RANLIB): replaced with AC_CHECK_TOOL.
* ltconfig.in (build): new variable to hold the build triplet
which is now checked for unless --no-verify is specified.
(--build): new argument to set the build triplet.
(ranlib): Prefer ${host_alias}-ranlib[.exe] if $build is different
to $host.
* doc/libtool.texi (Invoking ltconfig): Document --build option.
* NEWS: Note --build option.
* libtool.m4 (AC_PROG_LIBTOOL): added --with-pic flag
* ltconfig.in: new pic_mode variable and --prefer[-non]-pic flags,
fixed the strip check (reported by Keith Bostic <bostic@bostic.com>)
* ltmain.in (compile mode): build only PIC/non-PIC code depending
on pic_mode
* libltdl/README: document the supported dlopen interfaces
* doc/libtool.texi (tests): documented new tests
* tests/Makefile.am: added new tests
* tests/demo-pic.test: new test to test --with-pic
* tests/demo-nopic.test: new test to test --without-pic
* tests/build-relink2.test: variant of build-relink.test that
uses depdemo
* cdemo/main.c: "Welcome _to_ ..."
* mdemo/main.c: ditto
* libltdl/configure.in: support multiple dlopening mechanisms
at once
* libltdl/ltdl.c: prefix system dependent functions with "sys_"
to avoid symbol conflicts (libdld didn't work)
* libtool.m4 (AC_LIBLTDL_*): set INCLTDL to the path of ltdl.h
* ltconfig.in: check for dlopen with -ldl first
ltconfig if this is set.
(AC_LIBTOOL_WIN32_DLL): New macro required for libtool to attempt
a dll build on win32 hosts.
* ltconfig.in (--enable-win32-dll): new flag for the cli.
(cygwin*|mingw*|os2*, ltconfig_enable_win32_dll): if this is not set
to yes, then do not attempt to build shared libraries.
* doc/libtool.texi: document AC_LIBTOOL_WIN32_DLL.
* NEWS: noted new macro.
AC_ENABLE_STATIC, AC_ENABLE_FAST_INSTALL, AC_LIBLTDL_CONVENIENCE,
AC_LIBLTDL_INSTALLABLE): Warn if they appear after
AC_PROG_LIBTOOL. AC_LIBTOOL_SETUP, actually.
(AC_LIBTOOL_SETUP): Check whether DLOPEN support is to be enabled
at autoconf time, not configure time. Simplify code and
improve (?) help message about --disable-libtool-lock.
* ltconfig.in (cygwin*, file_magic_cmd): Use autoconf-located target
objdump tool. Track OBJDUMP like DLLTOOL and AS.
* ltconfig.in (cygwin*, deplibs_check_method): Accept
"architecture: i386" as optional suffix, for it is printed on a
separate line sometimes.
* ltmain.in (cygwin*, ltdll.c): Wrap DllMain declaration in extern "C".
* ltmain.in (deplibs_check_method=file_magic): Redirect stderr to
/dev/null, to suppress error messages from target objdump.
* doc/libtool.texi: removed hardcode_into_libs documentation
* libtool.m4: some DJGPP fixes
* ltconfig.in: ditto, reverted one of my previous patches: we need
to check for NM, removed the hardcode_into_libs support since
no platform seems to support it
* ltmain.in: some DJGPP fixes, removed the hardcode_into_libs support
* libtool.m4: check for main in libm instead of cos
* ltmain.in: cosmetic fixes, don't try to link libraries only once
(although it's not necessary on many platforms and looks ugly...),
the deplibs check is now optional
* libltdl/configure.in: read libtool --config only once,
merged AC_SYS_SYMBOL_UNDERSCORE+AC_SYS_NM_PARSE from libtool.m4
* libtool.m4: AC_SYS_SYMBOL_UNDERSCORE+AC_SYS_NM_PARSE were not
used, lt_dlopen and silent may be empty, AC_SYS_LIBTOOL_CYGWIN
no longer necessary
* ltconfig.in: NM is already checked in libtool.m4,
* ltmain.in: always link all static dependency_libs
* tests/Makefile.am: added deplibs.test
* tests/demo-exec.test, demo-inst.test: removed hell0
* tests/deplibs.test: new test to test the deplibs_check_method
* libtoolize.in: add the libtool scripts to libltdl.tar.gz
* libtool.m4: don't AC_SUBST(USE_SYMBOL_UNDERSCORE),
AC_CHECK_LIBM sets LIBM, AC_LIBLTDL_INSTALLABLE doesn't work
when libltdl is already installed
* *demo/Makefile.am: use LIBM
* *demo/configure.in: AC_SUBST LIBM
* libltdl/configure.in: use ac_cv_sys_symbol_underscore instead of
USE_SYMBOL_UNDERSCORE
* ltconfig.in: added link_all_deplibs variable
* doc/libtool.texi: document it
* ltmain.in: always search for libname.la - don't eval libname_spec,
when linking libraries against static ones just print a warning
and add them to dependency_libs, add -lc before deplibs,
always link all dependencies of a static library or if
link_all_deplibs is yes, hardcode library paths if
hardcode_into_libs is no, don't link against dependency_libs
that already are deplibs
* README: updated (BeOS support, no longer shared libraries
support for AmigaOS), cleanups, we have now two mailing lists
* REAMDE-alpha: autogen -> bootstrap, we have now two mailing lists
* THANKS: added Xavier Pianet
* doc/PLATFORMS: BeOS works
* doc/libtool.texi: we have now to two mailing lists,
updated -dlopen self documentation, documented libltdl's license,
put each author in a separate line,
inter-library dependencies on uninstalled libtool libraries are
now supported, cleanups and minor corrections
* libltdl/COPYING.LIB: new file
* libltdl/ltdl.[ch]: added special exception to the LGPL license
* libtool.spec: removed, it was outdated
* Makefile.am: removed libtool.spec
* ltmain.in: use TMPDIR when possible, create a subdirectory
in the temporary directory, added -export-symbols-regex to the help,
* NEWS: improved support for BeOS and Cygwin
* TODO: ILD branch was merged, all internal variables and macros
are now documented
* demo/Makefile.am: use $(LIBS) instead of -lm
* doc/libtool.texi: documented new variable hardcode_into_libs
and thread_safe_flag_spec, renamed all AM_ENABLE/DISABLE_* macros
to AC_*, documented AC_DISABLE_FAST_INSTALL and AC_LIBTOOL_DLOPEN
* libltdl/ltdl.c: added two new error messages (cannot_open_error,
cannot_close_error), use them where approriate,
BeOS support (thanks to Xavier Pianet), on BeOS search modules
additionally in ADDON_PATH
* libtool.m4: rewrote AC_CHECK_LIBM: BeOS and Cygwin don't have
libm and *-ncr-sysv4.3* requires libmw
* ltconfig.in: don't check for LoadLibrary, hardcode dlopen
configuration for BeOS and Cygwin
* ltmain.in: fix sourcing of .la files on Solaris
(patch by Raja R Harinath)
output of NM too
(global_symbol_to_cdecl): new variable; convert the output of
global_symbol_pipe to valid C declarations; on HP/UX, convert
text symbols to function declarations
* libtool.m4: similar modifications
* doc/libtool.texi: document new variable
* ltmain.in: use global_symbol_to_cdecl to generate lt_dlpreopened
symbols; avoid extracting symbol lists from dlpreopened files
twice; do not filter symbols from dlpreopened libraries
* TODO: fixed HP/UX dlpreopening problem
(AC_LIBTOOL_SETUP): if lt_dlopen=yes, add --enable-dlopen to
libtool_flags; drop --enable-dlopen-self
* ltconfig.in: perform all the dirty work of testing for dlopening
support, because we need platform-dependent equivalents for
-export-dynamic, for self dlopening, and -static, for static self
dlopening
(dlopen_self_static): new configuration variable that is set to
yes only if static programs can dlopen themselves
* ltmain.in (-static, -all-static): dlopen_self=dlopen_self_static
avoid introducing multiple --enable options when re-running
config.status
* libltdl/configure.in: if enable_ltdl_* is not set, assume no
* configure.in: if enable_ltdl_install is not set, enable it
configure-work that AC_PROG_LIBTOOL used to do; add
--cache-file=$cache_file to libtool_flags
(AC_PROG_LIBTOOL): call AC_LIBTOOL_SETUP, save the cache, run
ltconfig and reload the cache
* configure.in: run AC_LIBTOOL_SETUP, then set LIBTOOL_FLAGS to
libtool_flags
* ltconfig.in: support --cache-file switch. If it is used, load
the cache in the beginning and save it just before terminating
renamed convenience libltdl, dropped toinst hack for installable
* libltdl/Makefile.am: ditto
* libltdl/configure.in: ditto; abort if none of the macros is used
new macros
* NEWS: ditto
* libltdl/configure.in: if none of the new macros or configure
arguments are used, warn and build convenience library only
* libltdl/Makefile.am: conditionally build convenience libltdl.la
* mdemo/configure.in: use AC_LIBLTDL_CONVENIENCE
* mdemo/Makefile.am: refer to @LIBLTDL@
* demo/configure.in: use AC_LIBTOOL_DLOPEN
* libtool.m4: added AC_ENABLE/DISABLE_FAST_INSTALL macro
* ltconfig.in: added --disable-fast-install flag
* ltmain.in: partially reverted Alexandre's patch and implemented
on-demand linking in such a way that the old developer-friendly
linking style is optional,
don't hardcode library paths that are in the system search path,
fixed a typo in lib_search_path,
implemented -export-symbols-regex for programs
the next version of cygwin.
(sub_uncdir): removed. We use <drive>:/path/to/executable now.
* libtool.m4 (AC_PROG_LD): removed sub_uncdrive and sub_uncdir.
when dlopening the executable
* libtool.m4 (AC_LIBTOOL_DLOPEN): removed the redundant "yes: "
prefix for lt_cv_dlopen, renamed lt_cv_dlopen_LIBS
to lt_cv_dlopen_libs (more consistent)
* ltmain.in: implemented -dl[pre]open self, necessary for
lt_dlopen(NULL), generation of exported symbols was broken
trying in dl. Add the actual dlopening type to lt_cv_dlopen, and
add any needed libraries to lt_cv_dlopen_LIBS. Add test for
MS-Windows' LoadLibrary. Check whether a program can dlopen
itself only if we really have dlopen(), not some equivalent
function, but leave room for testing with other mechanisms.
(AC_PROG_LIBTOOL): assume some form of dlopen, but not
dlopen(NULL), is available if AC_LIBTOOL_DLOPEN is not used, for
backward compatibility.
* cdemo/foo1.c: renamed to foo.c
* libltdl/ltdl.c: eliminated lt_dltype, in presym_open():
search for @PROGRAM@ if filename == 0, in lt_dlopen():
fixed bug for filename == 0
* libltdl/ltdl.h: use __P macro for lt_dlmalloc/free
* libtool.m4: new macro AC_LIBTOOL_DLOPEN: checks for dlopen
and dlopen(NULL) support
* ltconfig.in: added new variables dlopen and dlopen_self,
--enable-dlopen[-self] flags for AC_LIBTOOL_DLOPEN
* ltmain.in: use dlopen[_self], dlpreopen files if there's no
dlopen support, build lt_preloaded_symbols only if
-dl[pre]open was used, include program symbols if -export-dynamic
was specified and there's no dlopen(NULL) support
* mdemo/configure.in: use AC_LIBTOOL_DLOPEN
* mdemo/main.c: demonstrate lt_dlopen(0)
this has a negative side-effect of causing automake to add MATHLIB
to every single Makefile. Let's use plain AC_CHECK_LIB, so that
LIBS get set, until we find a better alternative
* *demo/Makefile.am: remove $(MATHLIB)
* *demo/configure.in: use AC_CHECK_LIBM
* doc/libtool.texi: renamed file_magic_command to file_magic_cmd,
renamed archive_sym_cmds to archive_expsym_cmds
* ltconfig.in: ditto
* ltmain.in: ditto
* libltdl/ltdl.c: use lt_dlmalloc/free
* libltdl/ltdl.h: define lt_dlmalloc/free
* libtool.m4: added AC_CHECK_LIBM macro
* ltconfig.in: renamed archive_sym_cmds to archive_expsym_cmds,
added always_export_symbols, export_symbols_cmd, exclude_expsyms,
include_expsyms, removed archive_cmds for cygwin/mingw and AIX,
on Solaris store the exported symbols list in objdir
* ltmain.in: allow -export-symbols for modules, use thread_safe flag,
add include_expsyms to the exported symbols
addition to space as separator, and allow more than one space
between the symbol code and the symbol name; HP/UX's nm, for
example, uses two spaces
* ltconfig.in (global_symbol_pipe): ditto
(bsdi4, deplibs_check_method): variable name was misspelled
* libltdl/configure.in (libltdl_cv_preloaded_symbols): rewrite
test, so as not to depend on the way global_symbol_pipe is
initialized; the current test would get false positives, as
global_symbol_pipe was initialized `x=""', not `x='
* demo/configure.in: likewise
* depdemo/configure.in: likewise
* libltdl/configure.in: likewise
* mdemo/configure.in: likewise
* libltdl/ltdl.c: in find_module() check whether libdir is defined,
tryall_dlopen(): move deallocation of an already opened handle
to lt_dlopen(), allocate the directory in lt_dlopen() dynamically,
minor cleanups, fixed memory leak (name)
* libtool.m4: renamed all AM_ macros to AC_ and added aliases for
compatibilty, updated AC_SYS_NM_PARSE (no undefined symbols,
don't count the symbols)
* ltconfig.in: added thread_safe_flag_spec (not used yet),
added generic variable for linker options "linkopts" in
all archive_cmds
* ltmain.in: added -thread-safe flag (unused)
* ltconfig.in, ltmain.in: updated and fixed the patches below
1998-11-04 Thomas Tanner <tanner@gmx.de>
* mdemo/*: added new demo to demonstrate building of dlopenend
modules
* tests/Makefile.am, tests/mdemo*: added some tests for mdemo
1998-11-04 Gary V. Vaughan <gvaughan@oranda.demon.co.uk>
* demo/configure.in: added AC_EXEEXT macro so that the tests can
work on cywin32/mingw32 hosts. This requires the current CVS
autoconf
1998-11-04 Thomas Tanner <tanner@gmx.de>
* ltmain.in: New flag -export-symbols; new dlpreopen system
* demo/dlmain.c: removed dld_preloaded_symbol_count
1998-11-04 Ian Lance Taylor <ian@cygnus.com>
* ltmain.in: On installation, don't get confused if the same name
appears more than once in the list of library names.
1998-11-04 Ian Lance Taylor <ian@cygnus.com>
* ltconfig.in: Add objext and libext variables. Check for object
suffix. Check for mingw32* as well as cygwin32*. Use objext when
testing compiler. Add support for Visual C++ on cygwin32 when not
using gcc. Add objext, libext, and fix_srcfile_path to generated
libtool script.
* ltmain.in: Use .${objext} rather than .o. Use fix_srcfile_path
if it is set. Check for .obj as well as for .o, and for .lib as
well as for .a. Use .${libext} rather than .a when creating old
libraries.
* libtoolize.in: Change initial /bin/sh to @SHELL@.
* libtool.m4 (AM_PROG_LIBTOOL): Add AC_REQUIRE for
AC_CANONICAL_BUILD, so that autoconf doesn't get mixed up by the
AC_REQUIRE in AC_CHECK_TOOL.
1998-11-04 Ian Lance Taylor <ian@cygnus.com>
* ltconfig.in: Look in the right directory for libtool.c in
archive_cmds for cygwin32.
1998-11-04 Ian Lance Taylor <ian@cygnus.com>
* ltconfig.in: Fix cygwin32 support to avoid using a double
extension, to delete the def file, to set version_type to windows,
and to include versuffix in the DLL name.
* ltmain.in: Add support for a version_type of windows.
1998-11-04 Ian Lance Taylor <ian@cygnus.com>
* ltconfig.in: Add cygwin32 support.
* libtool.m4 (AM_PROG_LIBTOOL): Call AM_SYS_LIBTOOL_CYGWIN32 on a
cygwin32 host. Pass DLLTOOL and AS to ltconfig.
(AM_SYS_LIBTOOL_CYGWIN32): New macro.
supported.
* libtool.m4 (libtool-lock): new ARG_ENABLE; sets (need_locks)
* ltconfig.in (disable-lock): control need_locks
(hard_links): check whether hard-links can be used for locking
* ltmain.in (need_locks): use $output_obj.lock for locking
