Fix linker errors.

Stubbing out all OS* functions to stubs.cpp, these will likely have to
be replaced with the operating system's primitives for
locking/heaps/threads/etc.

Moved some generic globals into globals.cpp, not sure where they're
actually to be used.

Stub DSP functions

Stub JSUMemoryOutputStream, JORServer, Z2Audio

mDoExt stubs

add memcpy

add some more stubs, add extras c++ mangled functions

add extras.cpp

AR/AQ stubbing

stub DVD

stub CARD

more stubs, more extras

add missing mtx functions to dusk file

finish mtx

stub GX

KPAD and LC, also do pragma marks for better visualization

finish mtx, add a few more stubs

gf/wpad/vi

translate some matrix math from ppc to C

jorserver/debugpad/fap/dmsgobject

add m_Do_ext functions from debug block to separate file

make small janges to JSystem, does this need upstreaming

reorg DVD stubs

reorganize stubs by mark

src/dusk/extras.cpp

@@ -0,0 +1,18 @@
+// C++ Mangled version of extras.c
+#include <cstring>
+#include <cstdint>
+
+void *__memcpy(void* dest, void const* src, int n) {
+    return memcpy(dest, src, n);
+}
+
+void __dcbz(void* addr, int offset) {
+    // Gekko cache lines are 32 bytes.
+    // dcbz usually requires addr to be 32-byte aligned.
+    memset((char*)addr + offset, 0, 32); 
+}
+
+int __cntlzw(unsigned int val) {
+    if (val == 0) return 32; // PowerPC returns 32 if the input is 0
+    return __builtin_clz(val);
+}