Bug#1026045: Pointer truncation issue in DLOPEN_LOCAL_SCAN patch

[Florian Weimer]

Package: exim4
Version: 4.96-9

We are trying to port Fedora to a more modern variant of C.

  <https://fedoraproject.org/wiki/Changes/PortingToModernC>
  <https://fedoraproject.org/wiki/Toolchain/PortingToModernC>

This tripped up our Exim builds, and I see the same warning in the Exim
builds for Debian.  This patch should fix it:

diff --git a/src/local_scan.c b/src/local_scan.c
index 6ea5d2db841dbf19..42fbe79d02d9e9f5 100644
--- a/src/local_scan.c
+++ b/src/local_scan.c
@@ -14,6 +14,7 @@ extern uschar *local_scan_path;        /* Path to local_scan() library */
 
 #ifdef DLOPEN_LOCAL_SCAN
 #include <dlfcn.h>
+#include <stdlib.h>
 static int (*local_scan_fn)(int fd, uschar **return_text) = NULL;
 static int load_local_scan_library(void);
 #endif

As I said on the Fedora bug

  exim: pointer truncation bug in downstream-only
  exim-4.96-dlopen-localscan.patch patch
  <https://bugzilla.redhat.com/show_bug.cgi?id=2152978>

I think it's harmless because it only happens in case of a configuration
problem, but I'd thought to file this bug nevertheless.

Thanks,
Florian