Refactor new/delete overrides (#660)

Produce static library that only overrides new and delete. This allows for a static library to be added that only overrides new and delete.

src/snmalloc/override/new.cc

@@ -1,4 +1,4 @@
-#include "malloc.cc"
+#include "libc.h"
 
 #ifdef _WIN32
 #  ifdef __clang__
@@ -16,8 +16,6 @@
 #  endif
 #endif
 
-using namespace snmalloc;
-
 void* operator new(size_t size)
 {
   return snmalloc::libc::malloc(size);
@@ -70,25 +68,25 @@ void operator delete[](void* p, std::nothrow_t&)
 
 void* operator new(size_t size, std::align_val_t val)
 {
-  size = aligned_size(size_t(val), size);
+  size = snmalloc::aligned_size(size_t(val), size);
   return snmalloc::libc::malloc(size);
 }
 
 void* operator new[](size_t size, std::align_val_t val)
 {
-  size = aligned_size(size_t(val), size);
+  size = snmalloc::aligned_size(size_t(val), size);
   return snmalloc::libc::malloc(size);
 }
 
 void* operator new(size_t size, std::align_val_t val, std::nothrow_t&)
 {
-  size = aligned_size(size_t(val), size);
+  size = snmalloc::aligned_size(size_t(val), size);
   return snmalloc::libc::malloc(size);
 }
 
 void* operator new[](size_t size, std::align_val_t val, std::nothrow_t&)
 {
-  size = aligned_size(size_t(val), size);
+  size = snmalloc::aligned_size(size_t(val), size);
   return snmalloc::libc::malloc(size);
 }
 
@@ -104,12 +102,12 @@ void operator delete[](void* p, std::align_val_t) EXCEPTSPEC
 
 void operator delete(void* p, size_t size, std::align_val_t val) EXCEPTSPEC
 {
-  size = aligned_size(size_t(val), size);
+  size = snmalloc::aligned_size(size_t(val), size);
   snmalloc::libc::free_sized(p, size);
 }
 
 void operator delete[](void* p, size_t size, std::align_val_t val) EXCEPTSPEC
 {
-  size = aligned_size(size_t(val), size);
+  size = snmalloc::aligned_size(size_t(val), size);
   snmalloc::libc::free_sized(p, size);
 }