Squashed 'src/minisketch/' changes from 3472e2f5ec..eb37a9b8e7

eb37a9b8e7 Merge sipa/minisketch#87: Avoid copy in self-assign
fe6557642e Merge sipa/minisketch#88: build: Add `-Wundef`
8ea298bfa7 Avoid copy in self-assign
978a3d8869 build: Add `-Wundef`
3387044179 Merge sipa/minisketch#86: doc: fix typo in sketch_impl.h
15c2d13b60 doc: fix typo in sketch_impl.h
7be08b8a46 Merge sipa/minisketch#85: Fixes for integer precision loss
00fb4a4d83 Avoid or make integer precision conversion explicit
9d62a4d27c Avoid the need to cast/convert to size_t for vector operations
19e06cc7af Prevent overflows from large capacity/max_elements

git-subtree-dir: src/minisketch
git-subtree-split: eb37a9b8e79f9e49d73b96a49bf97a96d9eb676c

src/sketch.h

@@ -29,7 +29,7 @@ public:
     virtual ~Sketch() {}
     virtual size_t Syndromes() const = 0;
 
-    virtual void Init(int syndromes) = 0;
+    virtual void Init(size_t syndromes) = 0;
     virtual void Add(uint64_t element) = 0;
     virtual void Serialize(unsigned char*) const = 0;
     virtual void Deserialize(const unsigned char*) = 0;