Implement object packer for consistent hashing

[Al2Klimov]

No description provided.

[Al2Klimov]

Have I already complained about MSVC?

diff --git a/lib/base/object-packer.cpp b/lib/base/object-packer.cpp
index 2ff08e5da..988504fe7 100644
--- a/lib/base/object-packer.cpp
+++ b/lib/base/object-packer.cpp
@@ -33,15 +33,21 @@ using namespace icinga;
 // Just for the sake of code readability
 typedef std::vector<char> StringBuilder;

-static const union {
+union EndiannessDetector
+{
+       EndiannessDetector()
+       {
+               i = 1;
+       }
+
        int i;
        char buf[sizeof(int)];
-} endianness = {
-       .i = 1
 };

+static const EndiannessDetector l_EndiannessDetector;
+
 // Assumption: The compiler will optimize (away) if/else statements using this.
-#define MACHINE_LITTLE_ENDIAN (endianness.buf[0])
+#define MACHINE_LITTLE_ENDIAN (l_EndiannessDetector.buf[0])

 static void PackAny(const Value& value, StringBuilder& builder);

@@ -55,6 +61,19 @@ static inline void SwapBytes(char& a, char& b)
        b = c;
 }

+#if CHAR_MIN != 0
+union CharU2SConverter
+{
+       CharU2SConverter()
+       {
+               s = 0;
+       }
+
+       unsigned char u;
+       signed char s;
+};
+#endif
+
 /**
  * Avoid implementation-defined overflows during unsigned to signed casts
  */
@@ -63,12 +82,7 @@ static inline char UIntToByte(unsigned i)
 #if CHAR_MIN == 0
        return i;
 #else
-       union {
-               unsigned char u;
-               signed char s;
-       } converter = {
-                       .s = 0
-       };
+       CharU2SConverter converter;

        converter.u = i;
        return converter.s;
@@ -94,17 +108,30 @@ static inline void PackUInt64BE(uint_least64_t i, StringBuilder& builder)
        builder.insert(builder.end(), (char*)buf, (char*)buf + 8);
 }

+union Double2BytesConverter
+{
+       Double2BytesConverter()
+       {
+               buf[0] = 0;
+               buf[1] = 0;
+               buf[2] = 0;
+               buf[3] = 0;
+               buf[4] = 0;
+               buf[5] = 0;
+               buf[6] = 0;
+               buf[7] = 0;
+       }
+
+       double f;
+       char buf[8];
+};
+
 /**
  * Append the given double as big-endian IEEE 754 binary64
  */
 static inline void PackFloat64BE(double f, StringBuilder& builder)
 {
-       union {
-               double f;
-               char buf[8];
-       } converter = {
-                       .buf = {0, 0, 0, 0, 0, 0, 0, 0}
-       };
+       Double2BytesConverter converter;

        converter.f = f;