diff --git a/CMakeLists.txt b/CMakeLists.txt
index 236b972..2d7c476 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -236,7 +236,9 @@ if(PROXYRES_CURL AND (PROXYRES_EXECUTE OR PROXYRES_BUILD_CLI))
             add_subdirectory(${curl_SOURCE_DIR} ${curl_BINARY_DIR} EXCLUDE_FROM_ALL)
         endif()
 
-        add_library(CURL::libcurl ALIAS libcurl)
+        if(NOT TARGET CURL::libcurl)
+            add_library(CURL::libcurl ALIAS libcurl)
+        endif()
     endif()
 endif()
 
diff --git a/resolver.c b/resolver.c
index a2aef59..34a0bb6 100644
--- a/resolver.c
+++ b/resolver.c
@@ -92,7 +92,7 @@ static bool proxy_resolver_get_proxies_for_url_from_system_config(void *ctx, con
         } else {
             // Construct proxy list url using scheme associated with proxy's port if available,
             // otherwise continue to use scheme associated with the url.
-            const int32_t proxy_port = get_host_port(proxy, strlen(proxy), 0);
+            const uint16_t proxy_port = get_host_port(proxy, strlen(proxy), 0);
             const char *proxy_scheme = proxy_port ? get_port_scheme(proxy_port, scheme) : scheme;
 
             // Use proxy from settings
diff --git a/wpad_dhcp_posix.c b/wpad_dhcp_posix.c
index c4342fc..8139a20 100644
--- a/wpad_dhcp_posix.c
+++ b/wpad_dhcp_posix.c
@@ -24,6 +24,7 @@
 
 #ifdef _WIN32
 #  define socketerr WSAGetLastError()
+#  define ssize_t   int
 #else
 #  define socketerr   errno
 #  define SOCKET      int
@@ -168,15 +169,16 @@ static bool dhcp_send_inform(SOCKET sfd, uint32_t xid, net_adapter_s *adapter) {
     opts = dhcp_copy_option(opts, &opt_end);
 
     // Broadcast DHCP request
-    int32_t request_len = (int32_t)(opts - (uint8_t *)&request);
-    int sent = sendto(sfd, (const char *)&request, request_len, 0, (struct sockaddr *)&address, sizeof(address));
+    const ssize_t request_len = (ssize_t)(opts - (uint8_t *)&request);
+    const ssize_t sent =
+        sendto(sfd, (const char *)&request, request_len, 0, (struct sockaddr *)&address, sizeof(address));
     return sent == request_len;
 }
 
 static bool dhcp_read_reply(SOCKET sfd, uint32_t request_xid, dhcp_msg *reply) {
-    int response_len = recvfrom(sfd, (char *)reply, sizeof(dhcp_msg), 0, NULL, NULL);
+    const ssize_t response_len = recvfrom(sfd, (char *)reply, sizeof(dhcp_msg), 0, NULL, NULL);
 
-    if (response_len <= (int)(sizeof(dhcp_msg) - DHCP_OPT_MIN_LENGTH)) {
+    if (response_len <= (ssize_t)(sizeof(dhcp_msg) - DHCP_OPT_MIN_LENGTH)) {
         LOG_DEBUG("Unable to read DHCP reply (%d:%d)\n", response_len, socketerr);
         return false;
     }