diff -ur a/osdep.m4 b/osdep.m4
--- a/osdep.m4	2017-01-18 09:11:20.000000000 -0500
+++ b/osdep.m4	2023-10-21 12:43:59.464797030 -0400
@@ -381,6 +381,7 @@
 unset have_sa_len
 AC_MSG_CHECKING([for sa_len in sockaddr])
 AC_TRY_COMPILE([
+#include <stdint.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 ], [struct sockaddr sa;
@@ -397,12 +398,13 @@
    unset sa_len_type_found
    for type in uint8_t "unsigned char"; do
        AC_TRY_COMPILE([
+#include <stdint.h>
 #include <sys/types.h>
 #include <sys/socket.h>], [
 struct sockaddr sa;
 $type *sa_len_ptr;
 sa_len_ptr = &sa.sa_len;
-sa_len_ptr++; /* use to avoid warning/error */],
+(*sa_len_ptr)++; /* use to avoid warning/error */],
        [AC_DEFINE_UNQUOTED(sa_len_type, [$type], [sa_len type])
         sa_len_type_found=t
         break])
@@ -636,6 +638,7 @@
 		in_port_t, in_addr_t],
 		, ,
 [
+#include <stdint.h>
 #include <sys/types.h>
 #include <netinet/in.h>
 ])