bug#71916: 31.0.50; build failure on MINGW64

[Andy Moreton <andrewjmoreton@gmail.com>]

On Wed 03 Jul 2024, Eli Zaretskii wrote:

>> From: Andy Moreton <andrewjmoreton@gmail.com>
>> Date: Wed, 03 Jul 2024 19:02:06 +0100
>> 
>> On Wed 03 Jul 2024, Andrea Corallo wrote:
>> 
>> > leuven65 <leuven65@gmail.com> writes:
>> >
>> >> I found the latest version of both master and emacs-30 branch (from Monday) failed to be built on MINGW64 / windows10.
>> >> It failed when starting native compilation, error pops up "Cannot find libgccjit library" (from
>> >> comp-ensure-native-compiler), maybe the called function "load_gccjit_if_necessary / init_gccjit_functions" return error.
>> >>
>> >> But if to revert the change introduced by branch "savannah/scratch/windows-98" (merged on 2024/06/30), the build becomes
>> >> OK.
>> >>
>> >>  git revert 38179f85f8f7236d5de8d9a4333b6a1d4ded63f0
>> >>
>> >> So that maybe the issue is caused by the 3 commits in this branch.
>> >
>> > Hello leuven65,
>> >
>> > could you share the exact error you observe?
>> >
>> > Ccing Po Lo
>> >
>> > Thanks
>> >
>> >   Andrea
>> 
>> I've seen the same issue on emacs-30 and master branches. It seems to be
>> that emacs cannot find the libgccjit DLL after dumping.
>> 
>> Running emacs under gdb, and using a breakpoint on `redraw-display':
>> 
>> (gdb) r -Q
>> Starting program: C:\emacs\git\emacs\emacs-30\build\mingw64-x86_64-O2-native\src\emacs.exe -Q
>> [New Thread 11584.0x27b4]
>> [New Thread 11584.0x1f54]
>> [New Thread 11584.0x1ec8]
>> [New Thread 11584.0x2ad0]
>> [New Thread 11584.0x1a60]
>> 
>> Thread 1 hit Breakpoint 2, Fredraw_display () at C:/emacs/git/emacs/emacs-30/src/dispnew.c:3222
>> 
>> (gdb) pp Vlibrary_cache
>> ((gccjit) (gccjit . t))
>> 
>> It seems odd that there are two entries here.
>
> Thanks, I think I fixed this now on the emacs-30 branch.
>
>> There is code at the end of syms_of_emacs in emacs.c that changes
>> Vdynamic_library_alist as a workaround for something similar, so have
>> other changes made that ineffective ?
>
> No, the problem was that Vlibrary_cache was not re-initialized after
> loading the pdumper file.

Thanks Eli, confirmed as working again on emacs-30.

    AndyM