Use __attribute__ ((fallthrough)) to indicate switch case fall through
instead of a comment. This ensures that the fallthrough warning is not
triggered even if the file is pre-processed (hence stripping the
comments) before it is compiled.

The actual fallback implementation is hidden behind a FALLBACK macro in
case the compiler doesn't support it.

Finally, the -Wimplict-fallthrough warning was upgraded to only allow
the attribute to satisfy it; a comment alone is no longer sufficient.

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>

gcc defaults to using struct layouts that follow the native conventions,
even if __attribute__((packed)) is given. In order to get the layout we
expect, we need to tell gcc to always use the gcc struct layout, at
least for packed structs. To do this, we can use the gcc_struct
attribute.

This is important, not only for porting to windows, but also potentially
for other platforms, as the bugs resulting from struct layout
differences are rather subtle and hard to find.

Signed-off-by: Ulf Hermann <ulf.hermann@qt.io>

If so, define attribute_hidden to be empty. Also, use attribute_hidden
in all places where we hide symbols. If this attribute is missing, it
simply means that we cannot hide private symbols in the binary using
attributes. This disables some optimizations and may increase the risk
of symbol name clashes with other libraries, but is not fatal.

However, we still employ linker version scripts to explicitly define
the exported symbols. This serves much of the same purpose. Also, as
all our symbols are prefixed with the library name, and "__" for
private ones, the chance of clashes is low anyway.

Signed-off-by: Ulf Hermann <ulf.hermann@qt.io>

The -fsanitize=undefined check need to use AC_LINK_IFELSE to make sure
libubsan is installed. When doing undefined checking we should disable
ALLOW_UNALIGNED memory accesses to catch issues where we do unaligned
accesses by accident.

Signed-off-by: Mark Wielaard <mjw@redhat.com>

Due to missing symbol versioning support in uClibc calls to versioned
functions that internally call different version of themselves results
in infinite recursion.

Introduce macro SYMBOL_VERSIONING and use it instead of plain SHARED to
decide whether symbol versioning is needed. Control this macro
definition with new configure option --disable-symbol-versioning.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Mark Wielaard <mjw@redhat.com>

lib/
	* eu-config.h (COMPAT_VERSION_NEWPROTO): New.  Twice.

Signed-off-by: Jan Kratochvil <jan.kratochvil@redhat.com>

* Change name from "Red Hat elfutils" to "elfutils".
* Update license of standalone tools and test from GPLv2 to GPLv3+.
* Change license of libraries from GPLv2+exception to GPLv2/LGPLv3+.
* Add Developer Certificate of Origin based contributor policy.

top-level:

- COPYING: Upgraded from GPLv2 to GPLv3.
- CONTRIBUTING, COPYING-GPLv2, COPYING-LGPLv3: New files.
- NEWS: Added note about new contribution and license policy.
- Makefile.am: Updated to GPLv3, added new files to EXTRA_DIST.
- configure.ac: Update to GPLv3, changed AC_INIT name to 'elfutils'.

backends, lib, libasm, libcpu, libdw, libdwfl, libebl, libelf:

- All files updated to GPLv2/LGPLv3+. Except some very small files
  (<5 lines) which didn't have any headers at all before, the linker
  .maps files and the libcpu/defs files which only contain data and
  libelf/elf.h which comes from glibc and is under LGPLv2+.

config:

- elfutils.spec.in: Add new License: headers and new %doc files.
- Update all license headers to GPLv2/LGPLv3+ for files used by libs.

src, tests:

- All files updated to GPLv3+. Except for the test bz2 data files, the
  linker maps and script files and some very small files (<5 lines)
  that don't have any headers.

Signed-off-by: Richard Fontana <rfontana@redhat.com>
Signed-off-by: Mark Wielaard <mjw@redhat.com>

Rename --enable-tls to more appropriate --enable-thread-safety.