diff --git a/CMake/PickyWarnings.cmake b/CMake/PickyWarnings.cmake
index 270f05653b..36ce76b18f 100644
--- a/CMake/PickyWarnings.cmake
+++ b/CMake/PickyWarnings.cmake
@@ -436,6 +436,10 @@ if(CMAKE_C_COMPILER_ID STREQUAL "Clang" AND MSVC)
   endforeach()
 endif()
 
+if(DOS AND CMAKE_C_COMPILER_ID STREQUAL "GNU" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 10.0)
+  list(APPEND _picky "-Wno-arith-conversion")  # Avoid warnings in DJGPP's built-in FD_SET() macro
+endif()
+
 if(_picky_nocheck OR _picky)
   set(_picky_tmp "${_picky_nocheck}" "${_picky}")
   string(REPLACE ";" " " _picky_tmp "${_picky_tmp}")
diff --git a/configure.ac b/configure.ac
index b4485e7889..00696689bd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -598,6 +598,15 @@ if test "$compiler_id" = "INTEL_UNIX_C"; then
   #
 fi
 
+case $host in
+  *msdosdjgpp)
+    if test "$compiler_num" -ge "1000"; then
+      dnl Avoid warnings in DJGPP's built-in FD_SET() macro
+      CFLAGS="$CFLAGS -Wno-arith-conversion"
+    fi
+    ;;
+esac
+
 CURL_CFLAG_EXTRAS=""
 if test "$want_werror" = "yes"; then
   CURL_CFLAG_EXTRAS="-Werror"
diff --git a/docs/examples/sendrecv.c b/docs/examples/sendrecv.c
index 21a09b6584..5e4ef10b05 100644
--- a/docs/examples/sendrecv.c
+++ b/docs/examples/sendrecv.c
@@ -36,9 +36,6 @@
  */
 #ifdef __GNUC__
 #pragma GCC diagnostic ignored "-Wsign-conversion"
-#ifdef __DJGPP__
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
 #elif defined(_MSC_VER)
 #pragma warning(disable:4127)  /* conditional expression is constant */
 #endif
diff --git a/lib/cshutdn.c b/lib/cshutdn.c
index 84e5b2a116..b2c62e1309 100644
--- a/lib/cshutdn.c
+++ b/lib/cshutdn.c
@@ -480,17 +480,10 @@ void Curl_cshutdn_setfds(struct cshutdn *cshutdn,
         curl_socket_t sock = ps.sockets[i];
         if(!FDSET_SOCK(sock))
           continue;
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
         if(ps.actions[i] & CURL_POLL_IN)
           FD_SET(sock, read_fd_set);
         if(ps.actions[i] & CURL_POLL_OUT)
           FD_SET(sock, write_fd_set);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
         if((ps.actions[i] & (CURL_POLL_OUT | CURL_POLL_IN)) &&
            ((int)sock > *maxfd))
           *maxfd = (int)sock;
diff --git a/lib/multi.c b/lib/multi.c
index 901f1b6deb..e6b2d19041 100644
--- a/lib/multi.c
+++ b/lib/multi.c
@@ -1246,17 +1246,10 @@ CURLMcode curl_multi_fdset(CURLM *m,
         if(!FDSET_SOCK(ps.sockets[i]))
           /* pretend it does not exist */
           continue;
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
         if(ps.actions[i] & CURL_POLL_IN)
           FD_SET(ps.sockets[i], read_fd_set);
         if(ps.actions[i] & CURL_POLL_OUT)
           FD_SET(ps.sockets[i], write_fd_set);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
         if((int)ps.sockets[i] > this_max_fd)
           this_max_fd = (int)ps.sockets[i];
       }
diff --git a/src/tool_cb_rea.c b/src/tool_cb_rea.c
index 4683f70691..85b60864f9 100644
--- a/src/tool_cb_rea.c
+++ b/src/tool_cb_rea.c
@@ -65,14 +65,7 @@ static bool waitfd(int waitms, int fd)
   timeout.tv_usec = (int)((waitms % 1000) * 1000);
 
   FD_ZERO(&bits);
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
   FD_SET(fd, &bits);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
   if(!select(fd + 1, &bits, NULL, NULL, &timeout))
     return TRUE; /* timeout */
   return FALSE;
diff --git a/tests/libtest/lib530.c b/tests/libtest/lib530.c
index f41530e385..c2d1d3375b 100644
--- a/tests/libtest/lib530.c
+++ b/tests/libtest/lib530.c
@@ -233,14 +233,7 @@ static void t530_updateFdSet(struct t530_Sockets *sockets, fd_set *fdset,
 {
   int i;
   for(i = 0; i < sockets->count; ++i) {
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
     FD_SET(sockets->sockets[i], fdset);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
     if(*maxFd < sockets->sockets[i] + 1) {
       *maxFd = sockets->sockets[i] + 1;
     }
diff --git a/tests/libtest/lib582.c b/tests/libtest/lib582.c
index 1ba6b947fa..4ac7b903bd 100644
--- a/tests/libtest/lib582.c
+++ b/tests/libtest/lib582.c
@@ -180,14 +180,7 @@ static void t582_updateFdSet(struct t582_Sockets *sockets, fd_set *fdset,
 {
   int i;
   for(i = 0; i < sockets->count; ++i) {
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
     FD_SET(sockets->sockets[i], fdset);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
     if(*maxFd < sockets->sockets[i] + 1) {
       *maxFd = sockets->sockets[i] + 1;
     }
diff --git a/tests/libtest/lib758.c b/tests/libtest/lib758.c
index f6f371948e..13f83526da 100644
--- a/tests/libtest/lib758.c
+++ b/tests/libtest/lib758.c
@@ -279,14 +279,7 @@ static void t758_updateFdSet(struct t758_Sockets *sockets, fd_set *fdset,
 {
   int i;
   for(i = 0; i < sockets->count; ++i) {
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
     FD_SET(sockets->sockets[i], fdset);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
     if(*maxFd < sockets->sockets[i] + 1) {
       *maxFd = sockets->sockets[i] + 1;
     }
diff --git a/tests/server/mqttd.c b/tests/server/mqttd.c
index cff3d497ea..784bab4c3e 100644
--- a/tests/server/mqttd.c
+++ b/tests/server/mqttd.c
@@ -675,14 +675,7 @@ static bool mqttd_incoming(curl_socket_t listenfd)
     FD_ZERO(&fds_err);
 
     /* there is always a socket to wait for */
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
     FD_SET(sockfd, &fds_read);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
 
     do {
       /* select() blocking behavior call on blocking descriptors please */
diff --git a/tests/server/sockfilt.c b/tests/server/sockfilt.c
index 01548f173d..fb1282df03 100644
--- a/tests/server/sockfilt.c
+++ b/tests/server/sockfilt.c
@@ -953,14 +953,7 @@ static bool juggle(curl_socket_t *sockfdp,
   FD_ZERO(&fds_write);
   FD_ZERO(&fds_err);
 
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
   FD_SET((curl_socket_t)fileno(stdin), &fds_read);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
 
   switch(*mode) {
 
@@ -969,14 +962,7 @@ static bool juggle(curl_socket_t *sockfdp,
     /* server mode */
     sockfd = listenfd;
     /* there is always a socket to wait for */
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
     FD_SET(sockfd, &fds_read);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
     maxfd = (int)sockfd;
     break;
 
@@ -990,14 +976,7 @@ static bool juggle(curl_socket_t *sockfdp,
     }
     else {
       /* there is always a socket to wait for */
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
       FD_SET(sockfd, &fds_read);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
       maxfd = (int)sockfd;
     }
     break;
@@ -1007,14 +986,7 @@ static bool juggle(curl_socket_t *sockfdp,
     sockfd = *sockfdp;
     /* sockfd turns CURL_SOCKET_BAD when our connection has been closed */
     if(CURL_SOCKET_BAD != sockfd) {
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
       FD_SET(sockfd, &fds_read);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
       maxfd = (int)sockfd;
     }
     else {
diff --git a/tests/server/socksd.c b/tests/server/socksd.c
index 556fb47c62..91f8c119d9 100644
--- a/tests/server/socksd.c
+++ b/tests/server/socksd.c
@@ -649,37 +649,16 @@ static bool socksd_incoming(curl_socket_t listenfd)
     FD_ZERO(&fds_err);
 
     /* there is always a socket to wait for */
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
     FD_SET(sockfd, &fds_read);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
 
     for(i = 0; i < 2; i++) {
       if(c[i].used) {
         curl_socket_t fd = c[i].clientfd;
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
         FD_SET(fd, &fds_read);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
         if((int)fd > maxfd)
           maxfd = (int)fd;
         fd = c[i].remotefd;
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
         FD_SET(fd, &fds_read);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
         if((int)fd > maxfd)
           maxfd = (int)fd;
       }
diff --git a/tests/server/sws.c b/tests/server/sws.c
index 59f41c8e03..224cc9d888 100644
--- a/tests/server/sws.c
+++ b/tests/server/sws.c
@@ -1118,14 +1118,7 @@ static int sws_get_request(curl_socket_t sock, struct sws_httprequest *req)
           FD_ZERO(&input);
           FD_ZERO(&output);
           got = 0;
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
           FD_SET(sock, &input);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
           do {
             logmsg("Wait until readable");
             rc = select((int)sock + 1, &input, &output, NULL, &timeout);
@@ -1321,14 +1314,7 @@ static curl_socket_t connect_to(const char *ipaddr, unsigned short port)
       timeout.tv_sec = 1; /* 1000 ms */
 
       FD_ZERO(&output);
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
       FD_SET(serverfd, &output);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
       while(1) {
         rc = select((int)serverfd + 1, NULL, &output, NULL, &timeout);
         if(rc < 0 && SOCKERRNO != SOCKEINTR)
@@ -1453,14 +1439,7 @@ static void http_connect(curl_socket_t *infdp,
       /* listener socket is monitored to allow client to establish
          secondary tunnel only when this tunnel is not established
          and primary one is fully operational */
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
       FD_SET(rootfd, &input);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
       maxfd = rootfd;
     }
 
@@ -1470,28 +1449,14 @@ static void http_connect(curl_socket_t *infdp,
       if(clientfd[i] != CURL_SOCKET_BAD) {
         if(poll_client_rd[i]) {
           /* unless told not to do so, monitor readability */
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
           FD_SET(clientfd[i], &input);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
           if(clientfd[i] > maxfd)
             maxfd = clientfd[i];
         }
         if(poll_client_wr[i] && toc[i]) {
           /* unless told not to do so, monitor writability
              if there is data ready to be sent to client */
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
           FD_SET(clientfd[i], &output);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
           if(clientfd[i] > maxfd)
             maxfd = clientfd[i];
         }
@@ -1500,28 +1465,14 @@ static void http_connect(curl_socket_t *infdp,
       if(serverfd[i] != CURL_SOCKET_BAD) {
         if(poll_server_rd[i]) {
           /* unless told not to do so, monitor readability */
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
           FD_SET(serverfd[i], &input);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
           if(serverfd[i] > maxfd)
             maxfd = serverfd[i];
         }
         if(poll_server_wr[i] && tos[i]) {
           /* unless told not to do so, monitor writability
              if there is data ready to be sent to server */
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
           FD_SET(serverfd[i], &output);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
           if(serverfd[i] > maxfd)
             maxfd = serverfd[i];
         }
@@ -2343,14 +2294,7 @@ static int test_sws(int argc, char *argv[])
 
     for(socket_idx = 0; socket_idx < num_sockets; ++socket_idx) {
       /* Listen on all sockets */
-#ifdef __DJGPP__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Warith-conversion"
-#endif
       FD_SET(all_sockets[socket_idx], &input);
-#ifdef __DJGPP__
-#pragma GCC diagnostic pop
-#endif
       if(all_sockets[socket_idx] > maxfd)
         maxfd = all_sockets[socket_idx];
     }