math: fix minor warnings in half.h and vector.h.

src/lol/math/half.h

@@ -73,8 +73,8 @@ public:
     bool operator <=(half x) const { return (float)*this <= (float)x; }
     bool operator >=(half x) const { return (float)*this >= (float)x; }
 
-    bool operator !() const { return !(bool)*this; }
-    operator bool() const { return bits & 0x7fffu; }
+    bool operator !() const { return !(bits & 0x7fffu); }
+    operator bool() const { return !!*this; }
 
     inline half operator -() const { return makebits(bits ^ 0x8000u); }
     inline half operator +() const { return *this; }

src/lol/math/vector.h

@@ -1225,6 +1225,12 @@ static inline Quat<T> operator /(Quat<T> x, Quat<T> const &y)
     \
     /* DECLARE_ALL_VECTOR_COERCE_OPS_INNER(tname, long double, real) */
 
+/* Disable warning about unary operator applied to unsigned type */
+#if defined _MSC_VER
+#   pragma warning(push)
+#   pragma warning(disable: 4146)
+#endif
+
 DECLARE_ALL_NONVECTOR_OPS(Cmplx)
 DECLARE_ALL_NONVECTOR_OPS(Quat)
 
@@ -1232,6 +1238,10 @@ DECLARE_ALL_VECTOR_OPS(Vec2)
 DECLARE_ALL_VECTOR_OPS(Vec3)
 DECLARE_ALL_VECTOR_OPS(Vec4)
 
+#if defined _MSC_VER
+#   pragma warning(pop)
+#endif
+
 /* Disable warnings in the >= > etc. operators about comparing signed and
  * unsigned. Ideally we would like to get these warnings only when the
  * inlined operators are actually used, but they seem to be triggered at