lib/sys/module: Add support for weak symbols

We need a means of allowing Syslinux derivative-specific functions to
remain unresolved when there is no implementation for them. For
example, unload_pxe() is referenced by common code in com32/lib, but
is only implemented for PXELINUX. By marking unload_pxe() as __weak we
can substitute references with the undefined_symbol() function for
SYSLINUX, EXTLINUX and ISOLINUX. Provided that those references are
never executed everything works fine. However, if code calls actually
calls unload_pxe() from SYSLINUX, EXTLINUX or ISOLINUX an error
message is displayed and execution is halted.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

0 files changed, 0 insertions, 0 deletions