suppress glibc "use sysmacros.h for major" warning

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/include/libbb.h b/include/libbb.h
index 2e9ea46..b1fec01 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -45,7 +45,7 @@
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/types.h>
-#ifndef major
+#if !defined(major) || defined(__GLIBC__)
 # include <sys/sysmacros.h>
 #endif
 #include <sys/wait.h>