$ for f in /mingw64/bin/libgccjit-0.dll /mingw64/lib/libgccjit.dll.a ; do (nm -A "$f" | grep strsignal) || echo "Not found in $f" ; done
Not found in /mingw64/bin/libgccjit-0.dll
C:/msys64/mingw64/lib/libgccjit.dll.a:d025724.o:0000000000000000 I __imp_strsignal
C:/msys64/mingw64/lib/libgccjit.dll.a:d025724.o:0000000000000000 T strsignal
$ gdb ../dest/bin/emacs.exe
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Reading symbols from ../dest/bin/emacs.exe...
(gdb) rbreak strsignal
Breakpoint 1 at 0x4000ce210: file ../../emacs/src/sysdep.c, line 2616.
const char *safe_strsignal(int);
Breakpoint 2 at 0x400209fc8
<function, no debug info> strsignal;
(gdb)