[PATCH v2] build: Fix errors of TCP_REPAIR_* undeclared

[Yumei Huang <yuhuang@redhat.com>]

Based on an original patch by Dongsheng, fix the following errors on systems with glibc < 2.29:

tcp.c: In function ‘tcp_flow_repair_on’:
tcp.c:2787:38: error: ‘TCP_REPAIR_ON’ undeclared (first use in this function); did you mean ‘TCP_REPAIR’?
  if ((rc = repair_set(c, conn->sock, TCP_REPAIR_ON)))
                                      ^~~~~~~~~~~~~
                                      TCP_REPAIR
tcp.c:2787:38: note: each undeclared identifier is reported only once for each function it appears in
tcp.c: In function ‘tcp_flow_repair_off’:
tcp.c:2807:38: error: ‘TCP_REPAIR_OFF’ undeclared (first use in this function); did you mean ‘TCP_REPAIR’?
  if ((rc = repair_set(c, conn->sock, TCP_REPAIR_OFF)))
                                      ^~~~~~~~~~~~~~
                                      TCP_REPAIR
make: *** [Makefile:94: passt] Error 1

Link: https://bugs.passt.top/show_bug.cgi?id=121
Reported-by: Dongsheng <dongsheng.song@gmail.com>
Signed-off-by: Yumei Huang <yuhuang@redhat.com>
---
 linux_dep.h    | 6 ++++++
 passt-repair.c | 1 +
 2 files changed, 7 insertions(+)

diff --git a/linux_dep.h b/linux_dep.h
index 240f50a..1d9e166 100644
--- a/linux_dep.h
+++ b/linux_dep.h
@@ -135,6 +135,12 @@ struct tcp_info_linux {
 #define CLOSE_RANGE_UNSHARE	(1U << 1)
 #endif
 
+#ifndef TCP_REPAIR_ON
+#define TCP_REPAIR_ON		1
+#define TCP_REPAIR_OFF		0
+#define TCP_REPAIR_OFF_NO_WP	-1	/* Turn off without window probes */
+#endif
+
 __attribute__ ((weak))
 /* cppcheck-suppress funcArgNamesDifferent */
 int close_range(unsigned int first, unsigned int last, int flags) {
diff --git a/passt-repair.c b/passt-repair.c
index 8c59d7e..c3c140f 100644
--- a/passt-repair.c
+++ b/passt-repair.c
@@ -40,6 +40,7 @@
 #include <linux/seccomp.h>
 
 #include "seccomp_repair.h"
+#include "linux_dep.h"
 
 #define SCM_MAX_FD 253 /* From Linux kernel (include/net/scm.h), not in UAPI */
 #define REPAIR_EXT		".repair"
-- 
@@ -40,6 +40,7 @@
 #include <linux/seccomp.h>
 
 #include "seccomp_repair.h"
+#include "linux_dep.h"
 
 #define SCM_MAX_FD 253 /* From Linux kernel (include/net/scm.h), not in UAPI */
 #define REPAIR_EXT		".repair"
-- 
2.47.0