[ext-code-space][heap] Fix GCC build issue

Bug: v8:11880
Change-Id: Ibcb1d16cf613027b1a0f17a37825ef95acfe94c1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3041437
Auto-Submit: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75828}

src/heap/memory-chunk.cc

@@ -252,7 +252,9 @@ void MemoryChunk::ReleaseAllAllocatedMemory() {
 
 template V8_EXPORT_PRIVATE SlotSet* MemoryChunk::AllocateSlotSet<OLD_TO_NEW>();
 template V8_EXPORT_PRIVATE SlotSet* MemoryChunk::AllocateSlotSet<OLD_TO_OLD>();
+#ifdef V8_EXTERNAL_CODE_SPACE
 template V8_EXPORT_PRIVATE SlotSet* MemoryChunk::AllocateSlotSet<OLD_TO_CODE>();
+#endif  // V8_EXTERNAL_CODE_SPACE
 
 template <RememberedSetType type>
 SlotSet* MemoryChunk::AllocateSlotSet() {
@@ -277,7 +279,9 @@ SlotSet* MemoryChunk::AllocateSlotSet(SlotSet** slot_set) {
 
 template void MemoryChunk::ReleaseSlotSet<OLD_TO_NEW>();
 template void MemoryChunk::ReleaseSlotSet<OLD_TO_OLD>();
+#ifdef V8_EXTERNAL_CODE_SPACE
 template void MemoryChunk::ReleaseSlotSet<OLD_TO_CODE>();
+#endif  // V8_EXTERNAL_CODE_SPACE
 
 template <RememberedSetType type>
 void MemoryChunk::ReleaseSlotSet() {