Due to the changes in PR81878 builds of GCC8 and trunk are impossible
with Ada enabled[1][2].
The reason the patch breaks the bootstrap is due to how gnatlink receives it's
arguments.
gnatlink is usually invoked as
$(GNATLINK) -v gnatcmd -o ../../gnat$(exeext) \
--GCC="$(CC) $(ADA_INCLUDES)" --LINK="$(GCC_LINK)" $(TOOLS_LIBS)
so it passes $(CC) and $(GCC_LINK) as quoted arguments to the program.
Because of this quotation the msys2 shell does not translate any paths in
$(CC) and $(GCC_LINK) from their Unix version to their Windows version.
Furthermore because there are multiple paths in the values separated by space
and because the paths often contain a prefix like -L (e.g. -L/f/foo) we can't
use `fix_srcfile_path` to fix this.
An alternative solution would have been to create a stub program that echos the
commandline options it receives back, and calling this program with $(CC) and $(GCC_LINK)
unquoted to get them translated. However this was a bit more invasive.
So instead for native compilations we add -B../../ such that it picks up the lto plugin
from the previous built compiler. Since it's native there shouldn't be a mismatch here.
[1] https://github.com/Alexpux/MINGW-packages/pull/3877#issuecomment-408651809
[2] https://gcc.gnu.org/ml/gcc/2018-07/msg00410.html
gnattools/ChangeLog:
PR ada/81878
* Makefile.in (TOOLS_FLAGS_TO_PASS_NATIVE): Add -B ../../.
From-SVN: r265583
d4eb0305b8