[PATCH iproute2] ip address: Fix loop initial declarations are only allowed in C99

[Roi Dayan]

On some distros, i.e. rhel 7.6, compilation fails with the following:

ipaddress.c: In function ‘lookup_flag_data_by_name’:
ipaddress.c:1260:2: error: ‘for’ loop initial declarations are only allowed in 
C99 mode
  for (int i = 0; i < ARRAY_SIZE(ifa_flag_data); ++i) {
  ^
ipaddress.c:1260:2: note: use option -std=c99 or -std=gnu99 to compile your code

This commit fixes the single place needed for compilation to pass.

Fixes: 9d59c86e575b ("iproute2: ip addr: Organize flag properties structurally")
Signed-off-by: Roi Dayan <r...@mellanox.com>
---
 ip/ipaddress.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index 3b53933f4167..f97eaff3dbbf 100644
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c
@@ -1257,7 +1257,9 @@ static const struct ifa_flag_data_t {
 
 /* Returns a pointer to the data structure for a particular interface flag, or 
null if no flag could be found */
 static const struct ifa_flag_data_t* lookup_flag_data_by_name(const char* 
flag_name) {
-       for (int i = 0; i < ARRAY_SIZE(ifa_flag_data); ++i) {
+       unsigned int i;
+
+       for (i = 0; i < ARRAY_SIZE(ifa_flag_data); ++i) {
                if (strcmp(flag_name, ifa_flag_data[i].name) == 0)
                        return &ifa_flag_data[i];
        }
-- 
2.8.4