[RFC][PATCH] ftrace/scripts: Work around for addition of metag magic but not relocations

[Laura Abbott <labbott@redhat.com>]

glibc recently did a sync up (94e73c95d9b5 "elf.h: Sync with the gabi
webpage") that added a #define for EM_METAG but did not add relocations

This triggers build errors:

scripts/recordmcount.c: In function 'do_file':
scripts/recordmcount.c:466:28: error: 'R_METAG_ADDR32' undeclared (first use in this function)
  case EM_METAG:  reltype = R_METAG_ADDR32;
                            ^~~~~~~~~~~~~~
scripts/recordmcount.c:466:28: note: each undeclared identifier is reported only once for each function it appears in
scripts/recordmcount.c:468:20: error: 'R_METAG_NONE' undeclared (first use in this function)
     rel_type_nop = R_METAG_NONE;
                    ^~~~~~~~~~~~

Work around this change with some more #ifdefery for the relocations.

Signed-off-by: Laura Abbott <labbott@redhat.com>
---
I hit this while testing with a newer glibc. I'm not sure what the policy is
about glibc, so this might just serve as an FYI for anyone else who
is working on the bleeding edge.

Fedora bug is at https://bugzilla.redhat.com/show_bug.cgi?id=1354034 for the
curious.
---
 scripts/recordmcount.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index e1675927..42396a7 100644
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -33,10 +33,17 @@
 #include <string.h>
 #include <unistd.h>
 
+/*
+ * glibc synced up and added the metag number but didn't add the relocations.
+ * Work around this in a crude manner for now.
+ */
 #ifndef EM_METAG
-/* Remove this when these make it to the standard system elf.h. */
 #define EM_METAG      174
+#endif
+#ifndef R_METAG_ADDR32
 #define R_METAG_ADDR32                   2
+#endif
+#ifndef R_METAG_NONE
 #define R_METAG_NONE                     3
 #endif
 
-- 
2.7.4