Add an option to disable building with XFS support

Right now, if you have the xfs development headers installed,
they will be picked up. Add an option to disable this behaviour.

Fixes #1878

diff --git a/configure.ac b/configure.ac
index 2d4c68105ffcd59de132eafdbfe32156a976083b..e4329757eb51f8e9be83df89ca69aa7cd2fdc0d4 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -683,10 +683,26 @@ AC_CHECK_HEADERS([ \
   wordexp.h \
 ])
 
-AC_CHECK_HEADERS([xfs/xqm.h], [], [],
-[
-#define _GNU_SOURCE
-])
+# --enable-xfs {{{
+AC_ARG_ENABLE([xfs],
+  [AS_HELP_STRING([--enable-xfs], [xfs support in df plugin @<:@default=yes@:>@])],
+  [],
+  [enable_xfs="auto"]
+)
+
+if test "x$enable_xfs" != "xno"; then
+  AC_CHECK_HEADERS([xfs/xqm.h],
+    [],
+    [
+      if test "x$enable_xfs" = "xyes"; then
+        AC_MSG_ERROR([xfs/xqm.h not found])
+      fi
+    ],
+    [[#define _GNU_SOURCE]]
+  )
+fi
+
+# }}}
 
 # For the dns plugin
 AC_CHECK_HEADERS(arpa/nameser.h)