Sync 4.next from master

[users/jgh/exim.git] / src / OS / os.h-Linux

diff --git a/src/OS/os.h-Linux b/src/OS/os.h-Linux
index eb7036d0f9f76d204947b52af19bc1333b7a4e17..510865c66044c8eaa57db396e5486af9c88e6b8a 100644 (file)
--- a/src/OS/os.h-Linux
+++ b/src/OS/os.h-Linux
@@ -1,5 +1,12 @@
 /* Exim: OS-specific C header file for Linux */
 
+/* Some old systems we've received bug-reports for have a <limits.h> which
+does not pull in <features.h>.  Best to just pull it in now and have done
+with the issue. */
+
+#include <features.h>
+
+
 #define CRYPT_H
 #define GLIBC_IP_OPTIONS
 #define HAVE_MMAP
@@ -37,9 +44,6 @@ storage" as quickly as Exim thinks they are. */
 
 #define NEED_SYNC_DIRECTORY
 
-/* Other OS have "const" in here */
-#define ICONV_ARG2_TYPE char **
-
 #define os_find_running_interfaces os_find_running_interfaces_linux
 
 /* Need a prototype for the Linux-specific function. The structure hasn't
@@ -50,4 +54,24 @@ extern struct ip_address_item *os_find_running_interfaces_linux(void);
 
 #endif /* __linux__ */
 
+/* Some folks running "unusual" setups with very old libc environments have
+found that _GNU_SOURCE=1 before <features.h> is not sufficient to define some
+constants needed for 64-bit arithmetic.  If you encounter build errors based
+on LLONG_MIN being undefined and various other escape hatches have not helped,
+then change the 0 to 1 in the next block. */
+
+#if 0
+# define LLONG_MIN LONG_LONG_MIN
+# define LLONG_MAX LONG_LONG_MAX
+#endif
+
+#if _POSIX_C_SOURCE >= 200809L || _ATFILE_SOUCE
+# define EXIM_HAVE_OPENAT
+#endif
+
+#if defined(TCP_FASTOPEN) && !defined(MSG_FASTOPEN)
+# define MSG_FASTOPEN 0x20000000
+#endif
+
+
 /* End */