libbacktrace patch committed: Add clang optnone attribute

[Ian Lance Taylor]

The libbacktrace testsuite was not passing when run with current
versions of clang.  Add the optnone attribute to make it pass.  Add
-Wno-attributes and -Wno-unknown-attributes to disable warnings about
unrecognized function attributes.  Bootstrapped and ran libbacktrace
testsuite on x86_64-pc-linux-gnu.  Committed to mainline.

Ian

            * btest.c (test1, test3): Add optnone attribute.
            * edtest.c (test1): Likewise.
            * mtest.c (test1, test3): Likewise.
            * configure.ac: Use -Wno-attributes and -Wno-unknown-attributes.
            * configure: Regenerate.

67130485e51fb4391908dc8beb7259623a94fbd6
diff --git a/libbacktrace/btest.c b/libbacktrace/btest.c
index d9fc372d33d..c4b2db2cce2 100644
--- a/libbacktrace/btest.c
+++ b/libbacktrace/btest.c
@@ -49,7 +49,7 @@ POSSIBILITY OF SUCH DAMAGE.  */
 
 /* Test the backtrace function with non-inlined functions.  */
 
-static int test1 (void) __attribute__ ((noinline, noclone, unused));
+static int test1 (void) __attribute__ ((noinline, noclone, optnone, unused));
 static int f2 (int) __attribute__ ((noinline, noclone));
 static int f3 (int, int) __attribute__ ((noinline, noclone));
 
@@ -163,7 +163,7 @@ f13 (int f1line, int f2line)
 
 /* Test the backtrace_simple function with non-inlined functions.  */
 
-static int test3 (void) __attribute__ ((noinline, noclone, unused));
+static int test3 (void) __attribute__ ((noinline, noclone, optnone, unused));
 static int f22 (int) __attribute__ ((noinline, noclone));
 static int f23 (int, int) __attribute__ ((noinline, noclone));
 
diff --git a/libbacktrace/configure.ac b/libbacktrace/configure.ac
index 59e9c415db8..bfd7f35d2d2 100644
--- a/libbacktrace/configure.ac
+++ b/libbacktrace/configure.ac
@@ -144,7 +144,8 @@ AC_SUBST(EXTRA_FLAGS)
 
 ACX_PROG_CC_WARNING_OPTS([-W -Wall -Wwrite-strings -Wstrict-prototypes \
                          -Wmissing-prototypes -Wold-style-definition \
-                         -Wmissing-format-attribute -Wcast-qual],
+                         -Wmissing-format-attribute -Wcast-qual \
+                         -Wno-attributes -Wno-unknown-attributes],
                          [WARN_FLAGS])
 
 AC_ARG_ENABLE([werror],
diff --git a/libbacktrace/edtest.c b/libbacktrace/edtest.c
index d99b8a60295..b644d93788c 100644
--- a/libbacktrace/edtest.c
+++ b/libbacktrace/edtest.c
@@ -43,7 +43,7 @@ POSSIBILITY OF SUCH DAMAGE.  */
 
 #include "testlib.h"
 
-static int test1 (void) __attribute__ ((noinline, noclone, unused));
+static int test1 (void) __attribute__ ((noinline, noclone, optnone, unused));
 extern int f2 (int);
 extern int f3 (int, int);
 
diff --git a/libbacktrace/mtest.c b/libbacktrace/mtest.c
index 9afe7089514..f793391653d 100644
--- a/libbacktrace/mtest.c
+++ b/libbacktrace/mtest.c
@@ -47,7 +47,7 @@ POSSIBILITY OF SUCH DAMAGE.  */
 
 #include "testlib.h"
 
-static int test1 (void) __attribute__ ((noinline, noclone, unused));
+static int test1 (void) __attribute__ ((noinline, noclone, optnone, unused));
 static int f2 (int) __attribute__ ((noinline, noclone));
 static int f3 (int, int) __attribute__ ((noinline, noclone));
 
@@ -211,7 +211,7 @@ f3 (int f1line __attribute__ ((unused)), int f2line 
__attribute__ ((unused)))
 
 /* Test the backtrace_simple function with non-inlined functions.  */
 
-static int test3 (void) __attribute__ ((noinline, noclone, unused));
+static int test3 (void) __attribute__ ((noinline, noclone, optnone, unused));
 static int f22 (int) __attribute__ ((noinline, noclone));
 static int f23 (int, int) __attribute__ ((noinline, noclone));