Revert "lxc: remove dependency on headers >= 3.0"

This reverts commit 598d1e53c1a15bb983ed96a19db411bbcdfd97df.

[Peter: Seems like I ended up applying the wrong patch :/]
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/lxc/0002-src-lxc-utils.h-don-t-redefine-setns.patch

@@ -1,159 +0,0 @@
-From fc111c5df2ce573f6d01c2a78405455aa4bc766c Mon Sep 17 00:00:00 2001
-From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
-Date: Wed, 16 Mar 2016 11:47:51 +0100
-Subject: [PATCH] src/lxc/utils.h: don't redefine setns()
-
-The current logic in src/lxc/utils.h consists in implementing a
-setns() function if HAVE_SETNS is undefined. However, there are cases
-where the autoconf setns() check will fail (and therefore HAVE_SETNS
-will not be defined), but the C library does provide a setns()
-prototype. Unfortunately, this prototype conflicts with the one used
-internally in LXC. The C library headers define:
-
-extern int setns (int __fd, int __nstype) __THROW;
-
-While LXC defines:
-
-static inline int do_setns(int fd, int nstype)
-
-Which triggers the following build failures:
-
-utils.h:52:19: error: static declaration of 'setns' follows non-static declaration
- static inline int setns(int fd, int nstype)
-                   ^
-In file included from /home/test/buildroot2/output/host/usr/arm-buildroot-linux-gnueabi/sysroot/usr/include/sched.h:43:0,
-                 from bdev.c:38:
-/home/test/buildroot2/output/host/usr/arm-buildroot-linux-gnueabi/sysroot/usr/include/bits/sched.h:91:12: note: previous declaration of 'setns' was here
- extern int setns (int __fd, int __nstype) __THROW;
-
-In order to resolve this problem, we adopt the solution that was
-adopted by the gdb project at
-https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=a8c636cb54328fb9a71dcf27b66a7e7ab5443d88:
-the function defined by LXC is renamed to do_setns(), and calls
-setns() when available, or otherwise falls back on doing the system
-calls manually.
-
-Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
----
- src/lxc/attach.c       | 2 +-
- src/lxc/conf.c         | 4 ++--
- src/lxc/lxc_user_nic.c | 4 ++--
- src/lxc/start.c        | 2 +-
- src/lxc/utils.c        | 2 +-
- src/lxc/utils.h        | 9 ++++-----
- 6 files changed, 11 insertions(+), 12 deletions(-)
-
-diff --git a/src/lxc/attach.c b/src/lxc/attach.c
-index 436ae7a..953963f 100644
---- a/src/lxc/attach.c
-+++ b/src/lxc/attach.c
-@@ -260,7 +260,7 @@ static int lxc_attach_to_ns(pid_t pid, int which)
- 	}
- 
- 	for (i = 0; i < size; i++) {
--		if (fd[i] >= 0 && setns(fd[i], 0) != 0) {
-+		if (fd[i] >= 0 && do_setns(fd[i], 0) != 0) {
- 			saved_errno = errno;
- 
- 			for (j = i; j < size; j++)
-diff --git a/src/lxc/conf.c b/src/lxc/conf.c
-index 55c2fae..8c7f16f 100644
---- a/src/lxc/conf.c
-+++ b/src/lxc/conf.c
-@@ -2636,7 +2636,7 @@ void restore_phys_nics_to_netns(int netnsfd, struct lxc_conf *conf)
- 		SYSERROR("Failed to open monitor netns fd");
- 		return;
- 	}
--	if (setns(netnsfd, 0) != 0) {
-+	if (do_setns(netnsfd, 0) != 0) {
- 		SYSERROR("Failed to enter container netns to reset nics");
- 		close(oldfd);
- 		return;
-@@ -2647,7 +2647,7 @@ void restore_phys_nics_to_netns(int netnsfd, struct lxc_conf *conf)
- 			WARN("Error moving nic index:%d back to host netns",
- 					s->ifindex);
- 	}
--	if (setns(oldfd, 0) != 0)
-+	if (do_setns(oldfd, 0) != 0)
- 		SYSERROR("Failed to re-enter monitor's netns");
- 	close(oldfd);
- }
-diff --git a/src/lxc/lxc_user_nic.c b/src/lxc/lxc_user_nic.c
-index 6622db0..399e855 100644
---- a/src/lxc/lxc_user_nic.c
-+++ b/src/lxc/lxc_user_nic.c
-@@ -492,7 +492,7 @@ static int rename_in_ns(int pid, char *oldname, char **newnamep)
- 		fprintf(stderr, "Opening %s\n", nspath);
- 		goto out_err;
- 	}
--	if (setns(fd, 0) < 0) {
-+	if (do_setns(fd, 0) < 0) {
- 		fprintf(stderr, "setns to container network namespace\n");
- 		goto out_err;
- 	}
-@@ -519,7 +519,7 @@ static int rename_in_ns(int pid, char *oldname, char **newnamep)
- 		if (!*newnamep)
- 			goto out_err;
- 	}
--	if (setns(ofd, 0) < 0) {
-+	if (do_setns(ofd, 0) < 0) {
- 		fprintf(stderr, "Error returning to original netns\n");
- 		close(ofd);
- 		return -1;
-diff --git a/src/lxc/start.c b/src/lxc/start.c
-index fa905e2..2c76713 100644
---- a/src/lxc/start.c
-+++ b/src/lxc/start.c
-@@ -157,7 +157,7 @@ static int attach_ns(const int ns_fd[LXC_NS_MAX]) {
- 		if (ns_fd[i] < 0)
- 			continue;
- 
--		if (setns(ns_fd[i], 0) != 0)
-+		if (do_setns(ns_fd[i], 0) != 0)
- 			goto error;
- 	}
- 	return 0;
-diff --git a/src/lxc/utils.c b/src/lxc/utils.c
-index d9e769d..a696e0f 100644
---- a/src/lxc/utils.c
-+++ b/src/lxc/utils.c
-@@ -1091,7 +1091,7 @@ bool switch_to_ns(pid_t pid, const char *ns) {
- 		return false;
- 	}
- 
--	ret = setns(fd, 0);
-+	ret = do_setns(fd, 0);
- 	if (ret) {
- 		SYSERROR("failed to set process %d to %s of %d.", pid, ns, fd);
- 		close(fd);
-diff --git a/src/lxc/utils.h b/src/lxc/utils.h
-index 059026f..0f79ba0 100644
---- a/src/lxc/utils.h
-+++ b/src/lxc/utils.h
-@@ -47,11 +47,11 @@ extern char *get_rundir(void);
- #endif
- #endif
- 
--/* Define setns() if missing from the C library */
--#ifndef HAVE_SETNS
--static inline int setns(int fd, int nstype)
-+static inline int do_setns(int fd, int nstype)
- {
--#ifdef __NR_setns
-+#ifdef HAVE_SETNS
-+	return setns(fd, nstype);
-+#elif defined(__NR_setns)
- 	return syscall(__NR_setns, fd, nstype);
- #elif defined(__NR_set_ns)
- 	return syscall(__NR_set_ns, fd, nstype);
-@@ -60,7 +60,6 @@ static inline int setns(int fd, int nstype)
- 	return -1;
- #endif
- }
--#endif
- 
- /* Define unshare() if missing from the C library */
- #ifndef HAVE_UNSHARE
--- 
-2.6.4
-

package/lxc/Config.in

@@ -5,6 +5,7 @@ config BR2_PACKAGE_LXC
 	depends on BR2_USE_MMU # fork()
 	# build system forcefully builds a shared library
 	depends on !BR2_STATIC_LIBS
+	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_0 # libcap
 	help
 	  Linux Containers (LXC), provides the ability to group and isolate
 	  of a set of processes in a jail by virtualizing and accounting the
@@ -12,7 +13,8 @@ config BR2_PACKAGE_LXC
 
 	  https://linuxcontainers.org/
 
-comment "lxc needs a toolchain w/ threads, dynamic library"
+comment "lxc needs a toolchain w/ threads, headers >= 3.0, dynamic library"
 	depends on BR2_USE_MMU
 	depends on !BR2_TOOLCHAIN_HAS_THREADS \
+		|| !BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_0 \
 		|| BR2_STATIC_LIBS