vppinfra: Link against lib execinfo on FreeBSD

Type: improvement
Change-Id: Ie3d6cba886e0779949e8d574f82cff62abc7ebed
Signed-off-by: Tom Jones <thj@freebsd.org>
diff --git a/src/vppinfra/CMakeLists.txt b/src/vppinfra/CMakeLists.txt
index f34ceed..5878f06 100644
--- a/src/vppinfra/CMakeLists.txt
+++ b/src/vppinfra/CMakeLists.txt
@@ -229,7 +229,12 @@
    )
 endif()
 
-option(VPP_USE_EXTERNAL_LIBEXECINFO "Use external libexecinfo (useful for non-glibc targets)." OFF)
+if("${CMAKE_SYSTEM_NAME}" STREQUAL "FreeBSD")
+  option(VPP_USE_EXTERNAL_LIBEXECINFO "Use external libexecinfo (useful for non-glibc targets)." ON)
+else()
+  option(VPP_USE_EXTERNAL_LIBEXECINFO "Use external libexecinfo (useful for non-glibc targets)." OFF)
+endif()
+
 if(VPP_USE_EXTERNAL_LIBEXECINFO)
   set(EXECINFO_LIB execinfo)
 endif()