Change: Limit memory allocations for each Squirrel instance

This can avoid out-of-memory situations due to single scripts using up the entire address space.
Instead, scripts that go above the maximum are killed.
The maximum is default 1 GB per script, but can be configured by a setting.

src/3rdparty/squirrel/squirrel/sqmem.cpp

@@ -9,8 +9,10 @@
 #include "../../../core/alloc_func.hpp"
 #include "../../../safeguards.h"
 
-void *sq_vm_malloc(SQUnsignedInteger size){	return MallocT<char>((size_t)size); }
+#ifdef SQUIRREL_DEFAULT_ALLOCATOR
+void *sq_vm_malloc(SQUnsignedInteger size) { return MallocT<char>((size_t)size); }
 
-void *sq_vm_realloc(void *p, SQUnsignedInteger oldsize, SQUnsignedInteger size){ return ReallocT<char>(static_cast<char*>(p), (size_t)size); }
+void *sq_vm_realloc(void *p, SQUnsignedInteger oldsize, SQUnsignedInteger size) { return ReallocT<char>(static_cast<char*>(p), (size_t)size); }
 
-void sq_vm_free(void *p, SQUnsignedInteger size){	free(p); }
+void sq_vm_free(void *p, SQUnsignedInteger size) { free(p); }
+#endif