As far as the set of .cpp files which are using vecmat.h are
concerned, `Zero_vector` is out of reach for the compiler optimizer,
because it is extern / lives in a separate translation unit. An
expression like `x == Zero_vector` or `v = Zero_vector` thus has to
perform memory loads (for Zero_vector's x,y,z parts) before
comparison or copying, respectively. By using an immediate zero
vector `vector{}` instead, the unnecessary extra loads should go
away.
I present exhibit A:
```
void copyxx(vector *x) { *x = Zero_vector; }
4905e0: 48 8b 05 41 c0 56 00 movq 0x56c041(%rip),%rax # 9fc628 <Zero_vector>
4905e7: 48 89 07 movq %rax,(%rdi)
4905ea: 8b 05 40 c0 56 00 movl 0x56c040(%rip),%eax # 9fc630 <Zero_vector+0x8>
4905f0: 89 47 08 movl %eax,0x8(%rdi)
4905f3: c3 ret
```
vs.
```
void copyxx(vector *x) { *x = vector{}; }
4905c0: 48 c7 07 00 00 00 00 movq $0x0,(%rdi)
4905c7: c7 47 08 00 00 00 00 movl $0x0,0x8(%rdi)
4905ce: c3 ret
```
Devirtualization is an optimization in the generated assembly: when a
class C is polymorphic but also final, ``((C *)ptr)->func()`` can be
turned from an indirect into a static call.
scripts/Y2K.cpp:467:5: warning: deleting object of polymorphic class type
"LevelScript_0000" which has non-virtual destructor might cause undefined
behavior [-Wdelete-non-virtual-dtor]
467 | delete ((LevelScript_0000 *)ptr);
Due to ``#include "DallasFuncs.cpp"``, DF is recompiled 52 times.
Rework it to build just once. The compile time goes down for me
from 1m45.3s to 1m38.8s on my 1135G7 CPU running make -j8.
* Begin by marking functions and variables as static when needed.
* More work.
* More work.
* More pokes.
* More work.
* More work.
* Initial work on the netgames.
* Revert changes to the license header on source files.
* clutter.cpp poke.
* One final poke.
* Move some declarations to headers:
Move paged_in_count and paged_in_num to gamesequence.h
Move DoneLightInstance and StartLightInstance to polymodel.h
* Look over the AI script/plug-ins.
* Going over the changes one last time.
* Fix rebase errors.
* More migration from bare statics to static inlines.
The vast majority of this is fixing up `char *` that should be `const char *`
but a handful of other fixes, like potential buffer overflows that GCC
noticed, etc, were applied as well.
This removes `-Wno-write-strings` from CMakeLists.txt, as it is no longer
necessary, as there is no longer a flood of compiler warning spam when
building.
This does not fix all compiler warnings; there are still a handful, and they
are legitimate, but they can be dealt with in a future commit.
