* Always follow NEW_STORAGE code paths.
This removes the code paths for the pre-NEW_STORAGE code.
* Remove NEW_STORAGE from build system.
The code no longer refers to `NEW_STORAGE`, so we can remove
this from the build system.
* Move clang/gcc options into makefile-header.
This puts all of the shared options into a single place so that
we can easily update it.
* Add -fwrapv to the clang/gcc command lines.
This is a step along the way to fixing interlisp/medley#90.
Enabling `-fwrapv` will let overflow checks that rely upon undefined
behavior to work correctly. Without this, with modern versions of
clang and gcc, the overflow checks in the C code are eliminated
by the compiler, resulting in incorrect behavior on the part of
Maiko.
See the linked bug for details and discussion.
Hopefully, this usage of `-fwrapv` will go away once we're using
the correct compiler builtins to detect and handle overflow
correctly.
The FSERROR define is on all the time now. It was not controlling
all of the functionality, with many places setting Lisp_errnno
outside of the code controlled by the define.
