bdwgc: Add missing include to avoid musl build failures

(From OE-Core rev: 33459ffd0b5f3f303bcf8fb4dce817f6d73162a1)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-support/bdwgc/bdwgc/musl_header_fix.patch

@@ -0,0 +1,27 @@
+Add missing header to avoid:
+
+| 1472659610.016355: ../git/pthread_stop_world.c: In function 'GC_brief_async_signal_safe_sleep':
+| 1472659610.0540252: ../git/pthread_stop_world.c:397:22: error: storage size of 'tv' isn't known
+| 1472659610.0540252:        struct timeval tv;
+| 1472659610.0540252:                       ^~
+| 1472659610.054099: ../git/pthread_stop_world.c:397:22: warning: unused variable 'tv' [-Wunused-variable]
+| 1472659610.054099:        struct timeval tv;
+| 1472659610.054099:                       ^~
+| 1472659610.054099: Makefile:1530: recipe for target 'pthread_stop_world.lo' failed
+
+in musl builds.
+
+Upstream-Status: Pending
+
+Index: git/pthread_stop_world.c
+===================================================================
+--- git.orig/pthread_stop_world.c
++++ git/pthread_stop_world.c
+@@ -45,6 +45,7 @@
+ #include <semaphore.h>
+ #include <errno.h>
+ #include <unistd.h>
++#include <sys/time.h>
+ #include "atomic_ops.h"
+ 
+ /* It's safe to call original pthread_sigmask() here.   */

meta/recipes-support/bdwgc/bdwgc_7.6.0.bb

@@ -24,6 +24,7 @@ LIC_FILES_CHKSUM = "file://README.QUICK;md5=4f81f24ec69726c312487c2ac740e9e3"
 SRCREV = "8ac1d84a40eb7a431fec1b8097e3f24b48fb23fa"
 SRC_URI = "git://github.com/ivmai/bdwgc.git \
            file://0001-configure.ac-add-check-for-NO_GETCONTEXT-definition.patch \
+           file://musl_header_fix.patch \
           "
 
 FILES_${PN}-doc = "${datadir}"