common. Add one do-nothing element to each set. This ensures that
the linker realizes that they are linker sets rather than simple
commons, and makes it possible to link c++rt0.o into every shared
library regardless of whether it is a C++ library or not. Without
this change, the constructors and destructors in the main program
could be executed multiple times.
This change is going to make it possible to get rid of the
CPLUSPLUSLIB makefile variable once and for all. It is a piece of
the solution to PR gnu/3505 (gcc -shared). Finally, it fixes a
heretofore unreported bug: If CPLUSPLUSLIB was set in a makefile
for a C++ shared library that had no static constructors or
destructors in it, then the main program's constructors and
destructors would be executed multiple times.