fix duplicate FAST_FUNC FAST_FUNC

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/include/libbb.h b/include/libbb.h
index 51ac69e..c795e6a 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -393,7 +393,7 @@
 void bb_unsetenv(const char *key) FAST_FUNC;
 void xunlink(const char *pathname) FAST_FUNC;
 void xstat(const char *pathname, struct stat *buf) FAST_FUNC;
-int xopen(const char *pathname, int flags) FAST_FUNC FAST_FUNC;
+int xopen(const char *pathname, int flags) FAST_FUNC;
 int xopen3(const char *pathname, int flags, int mode) FAST_FUNC;
 int open_or_warn(const char *pathname, int flags) FAST_FUNC;
 int open3_or_warn(const char *pathname, int flags, int mode) FAST_FUNC;