ip utils: include headers with extern "C"

Change-Id: Ie292a09901bfdf3eaf8be7c2bc17189646677ed1
diff --git a/src/ip_utils.cpp b/src/ip_utils.cpp
index 91df414..6e7b69c 100644
--- a/src/ip_utils.cpp
+++ b/src/ip_utils.cpp
@@ -20,6 +20,7 @@
 
 #include <fmt/format.h>
 
+extern "C" {
 #include <sys/types.h>
 #include <unistd.h>
 #include <limits.h>
@@ -37,6 +38,7 @@
 #include <ifaddrs.h>
 #include <sys/ioctl.h>
 #endif
+}
 
 #ifndef HOST_NAME_MAX
 #ifdef MAX_COMPUTERNAME_LENGTH