configure.ac: fix configure tests broken with Clang 15 (implicit function declarations)

Clang 15 makes implicit function declarations fatal by default which
leads to some of tcpdump's configure tests silently failing/returning
the wrong result.

This adds the needed #includes to various tests for the functions used,
resolving the following errors:
```
net-analyzer/tcpdump-4.99.1/clang15.log:47:error: type specifier missing, defaults to 'int'; ISO C99 and later do not support implicit int [-Wimplicit-int]
net-analyzer/tcpdump-4.99.1/clang15.log:51:error: call to undeclared library function 'strcmp' with type 'int (const char *, const char *)'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
net-analyzer/tcpdump-4.99.1/clang15.log:55:error: call to undeclared library function 'sscanf' with type 'int (const char *restrict, const char *restrict, ...)'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
net-analyzer/tcpdump-4.99.1/clang15.log:68:error: call to undeclared library function 'memset' with type 'void *(void *, int, unsigned long)'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
net-analyzer/tcpdump-4.99.1/clang15.log:112:error: call to undeclared function 'ether_ntohost'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
net-analyzer/tcpdump-4.99.1/clang15.log:115:error: call to undeclared library function 'exit' with type 'void (int) __attribute__((noreturn))'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
```

Signed-off-by: Sam James <[email protected]>

diff --git a/configure b/configure
index 97fc63bb7373c3812b969dee8ce00c257e24dcd9..97084a38ba615cd6e993f6b349aa0f668038a08e 100755 (executable)
--- a/configure
+++ b/configure
@@ -4291,8 +4291,11 @@ else
 /* end confdefs.h.  */
 
 /* libsmi available check */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <smi.h>
-main()
+int main()
 {
   int current, revision, age, n;
   const int required = 2;
@@ -4915,6 +4918,7 @@ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
 
+#include <string.h>
 /* AF_INET6 available check */
 #include <sys/types.h>
 #ifdef _WIN32
@@ -6127,6 +6131,8 @@ else
 /* end confdefs.h.  */
 
                #include <netdb.h>
+               #include <netinet/ether.h>
+               #include <stdlib.h>
                #include <sys/types.h>
                #include <sys/param.h>
                #include <sys/socket.h>

diff --git a/configure.ac b/configure.ac
index 0d9782f8eff43f1daf4811219ce9f75318db5aeb..98195d597838adb78c8816c8158fce5b9cc5898a 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -87,8 +87,11 @@ if test "x$with_smi" != "xno" ; then
                        AC_TRY_RUN(
                                [
 /* libsmi available check */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <smi.h>
-main()
+int main()
 {
   int current, revision, age, n;
   const int required = 2;
@@ -264,6 +267,7 @@ AC_COMPILE_IFELSE(
     [
       AC_LANG_SOURCE(
        [[
+#include <string.h>
 /* AF_INET6 available check */
 #include <sys/types.h>
 #ifdef _WIN32
@@ -473,6 +477,8 @@ AC_CHECK_FUNCS(ether_ntohost, [
     AC_CACHE_CHECK(for buggy ether_ntohost, ac_cv_buggy_ether_ntohost, [
        AC_TRY_RUN([
                #include <netdb.h>
+               #include <netinet/ether.h>
+               #include <stdlib.h>
                #include <sys/types.h>
                #include <sys/param.h>
                #include <sys/socket.h>