Remove dependency on libws2_32 on Windows build

configure.ac

@@ -508,13 +508,6 @@ AC_CHECK_HEADERS([ \
   unistd.h \
 ])
 
-case "${host}" in
-  *mingw*)
-    # For ntohl, ntohs in Windows
-    AC_CHECK_HEADERS([winsock2.h])
-    ;;
-esac
-
 # Checks for typedefs, structures, and compiler characteristics.
 AC_TYPE_SIZE_T
 AC_TYPE_SSIZE_T
@@ -564,13 +557,6 @@ AM_CONDITIONAL([ENABLE_TINY_NGHTTPD],
                [ test "x${have_epoll}" = "xyes" &&
                  test "x${have_timerfd_create}" = "xyes"])
 
-dnl Windows library for winsock2
-case "${host}" in
-  *mingw*)
-    LIBS="$LIBS -lws2_32"
-    ;;
-esac
-
 ac_save_CFLAGS=$CFLAGS
 CFLAGS=
 

lib/nghttp2_net.h

@@ -37,8 +37,49 @@
 #include <netinet/in.h>
 #endif /* HAVE_NETINET_IN_H */
 
-#ifdef HAVE_WINSOCK2_H
-#include <winsock2.h>
-#endif /* HAVE_WINSOCK2_H */
+#include <nghttp2/nghttp2.h>
+
+#if defined(WIN32)
+/* Windows requires ws2_32 library for ntonl family functions.  We
+   define inline functions for those function so that we don't have
+   dependeny on that lib. */
+
+static inline uint32_t htonl(uint32_t hostlong) {
+  uint32_t res;
+  unsigned char *p = (unsigned char *)&res;
+  *p++ = hostlong >> 24;
+  *p++ = (hostlong >> 16) & 0xffu;
+  *p++ = (hostlong >> 8) & 0xffu;
+  *p = hostlong & 0xffu;
+  return res;
+}
+
+static inline uint16_t htons(uint16_t hostshort) {
+  uint16_t res;
+  unsigned char *p = (unsigned char *)&res;
+  *p++ = hostshort >> 8;
+  *p = hostshort & 0xffu;
+  return res;
+}
+
+static inline uint32_t ntohl(uint32_t netlong) {
+  uint32_t res;
+  unsigned char *p = (unsigned char *)&netlong;
+  res = *p++ << 24;
+  res += *p++ << 16;
+  res += *p++ << 8;
+  res += *p;
+  return res;
+}
+
+static inline uint16_t ntohs(uint16_t netshort) {
+  uint16_t res;
+  unsigned char *p = (unsigned char *)&netshort;
+  res = *p++ << 8;
+  res += *p;
+  return res;
+}
+
+#endif /* WIN32 */
 
 #endif /* NGHTTP2_NET_H */