[PATCH 3/3] tools/libxl: disable clang indentation check for the disk parser

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Clang 10 complains with:

13: error: misleading indentation; statement is not part of the previous 'if'
      [-Werror,-Wmisleading-indentation]
            if ( ! yyg->yy_state_buf )
            ^
libxlu_disk_l.c:1259:9: note: previous statement is here
        if ( ! yyg->yy_state_buf )
        ^

Due to the missing braces in single line statements and the wrong
indentation. Fix this by disabling the warning for that specific file.
I haven't found a way to force flex to add braces around single line
statements in conditional blocks.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
Please re-generate libxlu_disk_l.c before committing.
---
 tools/libxl/libxlu_disk_l.l | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tools/libxl/libxlu_disk_l.l b/tools/libxl/libxlu_disk_l.l
index 97039a2800..7a46f4a30c 100644
--- a/tools/libxl/libxlu_disk_l.l
+++ b/tools/libxl/libxlu_disk_l.l
@@ -36,6 +36,17 @@
 
 #define YY_NO_INPUT
 
+/* The code generated by flex is missing braces in single line expressions and
+ * is not properly indented, which triggers the clang misleading-indentation
+ * check that has been made part of -Wall since clang 10. In order to safely
+ * disable it on clang versions that don't have the diagnostic implemented
+ * also disable the unknown option and pragma warning. */
+#ifdef __clang__
+# pragma clang diagnostic ignored "-Wunknown-pragmas"
+# pragma clang diagnostic ignored "-Wunknown-warning-option"
+# pragma clang diagnostic ignored "-Wmisleading-indentation"
+#endif
+
 /* Some versions of flex have a bug (Fedora bugzilla 612465) which causes
  * it to fail to declare these functions, which it defines.  So declare
  * them ourselves.  Hopefully we won't have to simultaneously support
-- 
2.26.2