Merge #58: Move #ifdef HAVE_CLMUL guard outside of the EnableClmul definition

4d9db2b Move `#ifdef HAVE_CLMUL` guard outside of the EnableClmul definition (Hennadii Stepanov)

Pull request description:

  All of the `EnableClmul()` function call sites are guarded by the `HAVE_CLMUL` macro. Using the same guarding for its definition gets rid of a possible `-Wunused-function` compiler warning.

  Closes #53.

ACKs for top commit:
  sipa:
    utACK 4d9db2b

Tree-SHA512: 02eed1c9d2f23368f97fe8e4aaf63ecd287915bb36947af12e2860c2b29de17c21a027a26e9fce2dd666b719086277917c0d8b0ee64984a49afdd812d4264c45

Author: sipa

src/minisketch.cpp

@@ -63,9 +63,9 @@ enum class FieldImpl {
 #endif
 };
 
+#ifdef HAVE_CLMUL
 static inline bool EnableClmul()
 {
-#ifdef HAVE_CLMUL
 #ifdef _MSC_VER
     int regs[4];
     __cpuid(regs, 1);
@@ -74,10 +74,8 @@ static inline bool EnableClmul()
     uint32_t eax, ebx, ecx, edx;
     return (__get_cpuid(1, &eax, &ebx, &ecx, &edx) && (ecx & 0x2));
 #endif
-#else
-    return false;
-#endif
 }
+#endif
 
 Sketch* Construct(int bits, int impl)
 {