Embarcadero: Run at most one linker invocation at a time (#15620)

At least some versions (e.g. C++ Builder 5) of the bcc32 linker are known to
write temporary files with a constant name to the current directory (e.g.
"turboc.$ln").  (This can be verified by using Process Monitor to watch the
file writes that bcc32 / ilink32 / implib make).  This causes problems with
some generators that keep a constant current directory and run concurrent
linkers.

For example, the Ninja generator, by default, always has the current directory
set to the top of the build tree - resulting in conflicts between the linkers
that are simultaneously trying to write to "turboc.$ln".  Symptoms include
direct errors regarding the "turboc.$ln" file, or later build steps failing due
to corrupted output from previous links that happened to link "successfully."

This is not a problem for the Borland Makefiles generator which does not
run jobs in parallel.  For the Ninja generator, work around this problem
by using a link job pool of size 1.

0 files changed, 0 insertions, 0 deletions