Merge pull request #1040 from cdavis5e/fix-ios-build

Fix iOS/tvOS build.
diff --git a/MoltenVK/MoltenVK/Commands/MVKCommandEncodingPool.mm b/MoltenVK/MoltenVK/Commands/MVKCommandEncodingPool.mm
index 75c8c48..b1a5a26 100644
--- a/MoltenVK/MoltenVK/Commands/MVKCommandEncodingPool.mm
+++ b/MoltenVK/MoltenVK/Commands/MVKCommandEncodingPool.mm
@@ -202,12 +202,14 @@
     [_mtlFillBufferComputePipelineState release];
     _mtlFillBufferComputePipelineState = nil;
 
+#if MVK_MACOS
     [_mtlClearColorImageComputePipelineState[0] release];
     [_mtlClearColorImageComputePipelineState[1] release];
     [_mtlClearColorImageComputePipelineState[2] release];
     _mtlClearColorImageComputePipelineState[0] = nil;
     _mtlClearColorImageComputePipelineState[1] = nil;
     _mtlClearColorImageComputePipelineState[2] = nil;
+#endif
 
     [_mtlCopyBufferToImage3DDecompressComputePipelineState[0] release];
     [_mtlCopyBufferToImage3DDecompressComputePipelineState[1] release];