igc: trying to chase a crash

[Óscar Fuentes]

I'm using scratch/igc on and off since some weeks for work (mostly
Dart/Flutter code edition with lsp-mode, quite stressing for the GC
system). Today it crashed, so I launched it again under gdb, and there
it SIGSEGVs consistently while processing the init files. That means
that it SIGSEGVs at the same point every time I try.

So I went to build it in debug mode to obtain a good backtrace, but the
build fails:

../../emacs/src/marker.c: In function ‘buf_bytepos_to_charpos’:
../../emacs/src/marker.c:389:18: error: invalid operands to binary && (have 
‘int’ and ‘Lisp_Object’)
  389 |       if (record && BUF_MARKERS (b))
      |           ~~~~~~ ^~
      |           |
      |           int

$ gcc --version
gcc (Debian 14.2.0-8) 14.2.0

$ uname -a
Linux sky 6.11.5-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.11.5-1 (2024-10-27) 
x86_64 GNU/Linux

$ ../emacs/configure CPPFLAGS=-I/home/oscar/lib/mps/include 
LDFLAGS=-L/home/oscar/lib/mps/lib --with-native-compilation --with-tree-sitter 
--without-toolkit-scroll-bars --with-x-toolkit=lucid --with-modules 
--without-imagemagick --with-mps=yes --enable-checking='yes,glyphs' 
--enable-check-lisp-object-type CFLAGS='-O0 -g3'

The igc/branch is updated (commit 0756b1f2f5452d715396f).

So right now here igc runs when executed from the shell, but crashes on
startup when executed from gdb. And builds succesfully in release mode,
but doesn't in debug mode.

I wonder if either my build config is too infrequent or nobody is
testing igc lately?