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

src/common/mac/byteswap.h

 // -*- mode: c++ -*-
 
 // Copyright (c) 2010, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
@@ skipping 18 matching lines @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Original author: Jim Blandy <jim@mozilla.com> <jimb@red-bean.com>
 
 // byteswap.h: Overloaded functions for conveniently byteswapping values.
 
 #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); }
 static inline uint32_t ByteSwap(uint32_t v) { return OSSwapInt32(v); }
 static inline uint64_t ByteSwap(uint64_t v) { return OSSwapInt64(v); }
 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_