1 files changed, 23 insertions, 5 deletions

diff --git a/contrib/libpcap/ftmacros.h b/contrib/libpcap/ftmacros.h
index cd3daebdf175..7975463b3a69 100644
--- a/contrib/libpcap/ftmacros.h
+++ b/contrib/libpcap/ftmacros.h
@@ -45,7 +45,12 @@
  * namespace to the maximum extent possible"?
  */
 #if defined(sun) || defined(__sun)
-  #define __EXTENSIONS__
+  /*
+   * On Solaris Clang defines __EXTENSIONS__ automatically.
+   */
+  #ifndef __EXTENSIONS__
+    #define __EXTENSIONS__
+  #endif
 
   /*
    * We also need to define _XPG4_2 in order to get
@@ -83,14 +88,18 @@
    * least with HP's C compiler; hopefully doing so won't make it
    * *not* work with *un*-threaded code.
    */
-#elif defined(__linux__) || defined(linux) || defined(__linux)
+#else
   /*
    * Turn on _GNU_SOURCE to get everything GNU libc has to offer,
-   * including asprintf().
+   * including asprintf(), if we're using GNU libc.
    *
    * Unfortunately, one thing it has to offer is a strerror_r()
    * that's not POSIX-compliant, but we deal with that in
    * pcap_fmt_errmsg_for_errno().
+   *
+   * We don't limit this to, for example, Linux and Cygwin, because
+   * this might, for example, be GNU/HURD or one of Debian's kFreeBSD
+   * OSes ("GNU/FreeBSD").
    */
   #define _GNU_SOURCE
 
@@ -101,9 +110,18 @@
    * don't whine about _BSD_SOURCE being deprecated; we still have
    * to define _BSD_SOURCE to handle older versions of GNU libc that
    * don't support _DEFAULT_SOURCE.
+   *
+   * But, if it's already defined, don't define it, so that we don't
+   * get a warning of it being redefined if it's defined as, for
+   * example, 1.
    */
-  #define _DEFAULT_SOURCE
-  #define _BSD_SOURCE
+  #ifndef _DEFAULT_SOURCE
+    #define _DEFAULT_SOURCE
+  #endif
+  /* Avoid redefining _BSD_SOURCE if it's already defined as for ex. 1 */
+  #ifndef _BSD_SOURCE
+    #define _BSD_SOURCE
+  #endif
 #endif
 
 #endif