libxfs: warn about deprecation of irix, freebsd, darwin

It's not clear that anyone is using these platforms or if
they even build at this point.  Get someone's attention if
they are trying to use it.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/libxfs/darwin.c b/libxfs/darwin.c
index 16d2c35..396477e 100644
--- a/libxfs/darwin.c
+++ b/libxfs/darwin.c
@@ -26,6 +26,10 @@
 int platform_has_uuid = 1;
 extern char *progname;
 
+#warning "Darwin support is deprecated and planned for removal in July 2018"
+#warning "Contact linux-xfs@vger.kernel.org if you'd like to maintain this port"
+#error   "Remove this line if you'd like to continue the build"
+
 int
 platform_check_ismounted(char *name, char *block, struct stat *s, int verbose)
 {
diff --git a/libxfs/freebsd.c b/libxfs/freebsd.c
index 5b9ef29..d9fc837 100644
--- a/libxfs/freebsd.c
+++ b/libxfs/freebsd.c
@@ -26,6 +26,10 @@
 int platform_has_uuid = 1;
 extern char *progname;
 
+#warning "FreeBSD support is deprecated and planned for removal in July 2018"
+#warning "Contact linux-xfs@vger.kernel.org if you'd like to maintain this port"
+#error   "Remove this line if you'd like to continue the build"
+
 int
 platform_check_ismounted(char *name, char *block, struct stat *s, int verbose)
 {
diff --git a/libxfs/irix.c b/libxfs/irix.c
index 0f14aec..4ad68d5 100644
--- a/libxfs/irix.c
+++ b/libxfs/irix.c
@@ -24,6 +24,10 @@
 extern char *progname;
 extern int64_t findsize(char *);
 
+#warning "IRIX support is deprecated and planned for removal in July 2018"
+#warning "Contact linux-xfs@vger.kernel.org if you'd like to maintain this port"
+#error   "Remove this line if you'd like to continue the build"
+
 int
 platform_check_ismounted(char *name, char *block, struct stat *s, int verbose)
 {