The C standard treats an empty variable argument list as a single, empty
argument, so PP_NARGS() currently expands to 1. But this is surprising,
especially for PP_OVERLOAD(). Use the , ##__VA_ARGS__ GNU C extension to
make PP_NARGS() expand to 0 instead. (We could also use __VA_OPT__(,) to
achieve the same thing. It has the advantage of being standardized for
C23, but the huge disadvantage that it's only available on relatively
recent versions of GCC and Clang.) Also check that the extension is
supported in configure.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
drgn is currently licensed as GPLv3+. Part of the long term vision for
drgn is that other projects can use it as a library providing
programmatic interfaces for debugger functionality. A more permissive
license is better suited to this goal. We decided on LGPLv2.1+ as a good
balance between software freedom and permissiveness.
All contributors not employed by Meta were contacted via email and
consented to the license change. The only exception was the author of
commit c4fbf7e589 ("libdrgn: fix for compilation error"), who did not
respond. That commit reverted a single line of code to one originally
written by me in commit 640b1c011d ("libdrgn: embed DWARF index in
DWARF info cache").
Signed-off-by: Omar Sandoval <osandov@osandov.com>
The overloaded version is slower to compile, and we don't actually need
it. We can add a variadic version if we need to in the future. Also add
the script used to generate the macros.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
