Fix Mac Breakpad host tools to build in Linux cross-compile

src/common/mac/byteswap.h

Index: src/common/mac/byteswap.h
diff --git a/src/common/mac/byteswap.h b/src/common/mac/byteswap.h
index a5d745b3cad5e27b79884e81609d49132d960a01..b7bbc0b95bbd8c3c4fb1615ca8fb0b76b9d37453 100644
--- a/src/common/mac/byteswap.h
+++ b/src/common/mac/byteswap.h
@@ -36,6 +36,7 @@
 #ifndef COMMON_MAC_BYTESWAP_H_
 #define COMMON_MAC_BYTESWAP_H_
 
+#ifdef __APPLE__
 #include <libkern/OSByteOrder.h>
 
 static inline uint16_t ByteSwap(uint16_t v) { return OSSwapInt16(v); }
@@ -45,4 +46,28 @@ static inline int16_t  ByteSwap(int16_t  v) { return OSSwapInt16(v); }
 static inline int32_t  ByteSwap(int32_t  v) { return OSSwapInt32(v); }
 static inline int64_t  ByteSwap(int64_t  v) { return OSSwapInt64(v); }
 
+#elif defined(__linux__)
+// For NXByteOrder
+#include <architecture/byte_order.h>
+#include <stdint.h>
+#include <endian.h>
+#include_next <byteswap.h>
+
+static inline uint16_t ByteSwap(uint16_t v) { return bswap_16(v); }
+static inline uint32_t ByteSwap(uint32_t v) { return bswap_32(v); }
+static inline uint64_t ByteSwap(uint64_t v) { return bswap_64(v); }
+static inline int16_t  ByteSwap(int16_t  v) { return bswap_16(v); }
+static inline int32_t  ByteSwap(int32_t  v) { return bswap_32(v); }
+static inline int64_t  ByteSwap(int64_t  v) { return bswap_64(v); }
+
+static inline NXByteOrder NXHostByteOrder() {
+#ifdef __LITTLE_ENDIAN
+  return NX_LittleEndian;
+#else
+  return NX_BigEndian;
+#endif
+}
+
+#endif  // __APPLE__
+
 #endif  // COMMON_MAC_BYTESWAP_H_