fix libsodium cross compile

cmake/DownloadLibSodium.cmake

@@ -12,12 +12,19 @@ file(MAKE_DIRECTORY ${LIBSODIUM_PREFIX}/include)
 
 include(ExternalProject)
 include(ProcessorCount)
+
+set(SODIUM_CONFIGURE ./configure --prefix=${LIBSODIUM_PREFIX} --enable-static --disable-shared CC=${CMAKE_C_COMPILER})
+if (LIBSODIUM_CROSS_TARGET)
+    set(SODIUM_CONFIGURE ${SODIUM_CONFIGURE} --target=${LIBSODIUM_CROSS_TARGET} --host=${LIBSODIUM_CROSS_TARGET})
+endif()
+
+
 ExternalProject_Add(libsodium_external
     BUILD_IN_SOURCE ON
     PREFIX ${LIBSODIUM_PREFIX}
     URL ${LIBSODIUM_URL}
     URL_HASH ${LIBSODIUM_HASH}
-    CONFIGURE_COMMAND ./configure --prefix=${LIBSODIUM_PREFIX} --enable-static --disable-shared
+    CONFIGURE_COMMAND ${SODIUM_CONFIGURE}
     BUILD_COMMAND make -j${PROCESSOR_COUNT}
     INSTALL_COMMAND ${MAKE}
     BUILD_BYPRODUCTS ${LIBSODIUM_PREFIX}/lib/libsodium.a ${LIBSODIUM_PREFIX}/include

contrib/cross/mingw.cmake

@@ -2,6 +2,7 @@ set(CMAKE_SYSTEM_NAME Windows)
 set(TOOLCHAIN_PREFIX x86_64-w64-mingw32)
 set(TOOLCHAIN_SUFFIX "-posix")
 set(WIN64_CROSS_COMPILE ON)
+set(LIBSODIUM_CROSS_TARGET x86_64-w64-mingw32)
 
 set(TOOLCHAIN_PATHS
  /usr/${TOOLCHAIN_PREFIX}

contrib/cross/mingw32.cmake

@@ -2,6 +2,7 @@ set(CMAKE_SYSTEM_NAME Windows)
 set(TOOLCHAIN_PREFIX i686-w64-mingw32)
 set(TOOLCHAIN_SUFFIX "")
 set(WOW64_CROSS_COMPILE ON)
+set(LIBSODIUM_CROSS_TARGET i686-w64-mingw32)
 
 set(TOOLCHAIN_PATHS
   /usr/${TOOLCHAIN_PREFIX}

llarp/util/endian.hpp

@@ -48,6 +48,9 @@
 #define le64toh(x) OSSwapLittleToHostInt64(x)
 #elif defined(_WIN32)
 #include <winsock2.h>
+#ifndef __LITTLE_ENDIAN__
+#define __LITTLE_ENDIAN__
+#endif
 #define htobe16(x) htons(x)
 #define htole16(x) (x)
 #define be16toh(x) ntohs(x)