My Debian upgrade greeted me with this:
As of gcc-2.95, optimisation at level 2 (-O2) and higher includes an
optimisation which breaks C code that does not adhere to the C standard.
Such code occurs in the Linux kernel, and probably other places.
To compile the kernel (and probably other packages) with -O2 or better
optimisation, you need to add
'-fno-strict-aliasing'
to the compile line (e.g. the CFLAGS settings in ...linux/Makefile).
Before submitting a bug report for gcc, check if the package compiles with
this flag added. If yes, submit a bug report for the package. More
information can be found in /usr/share/doc/gcc/README.Debian.gz
[Press RETURN to continue]
Has anyone tried to compile and run XEmacs with and without aliasing
and with and without union type to see if it works?