fix getentropy()

Add missing header in commit 19fe75f0ab09c9661ff03738579171624fc35018

Reported-By: Ronald Wahl <ronald.wahl@legrand.com>

libc/sysdeps/linux/common/Makefile.in

@@ -27,6 +27,7 @@ CSRC-$(UCLIBC_LINUX_SPECIFIC) += \
 	eventfd_write.c \
 	fanotify.c \
 	getrandom.c \
+	getentropy.c \
 	inotify.c \
 	ioperm.c \
 	iopl.c \

libc/sysdeps/linux/common/getentropy.c

@@ -12,6 +12,7 @@
 #include <errno.h>
 #include <unistd.h>
 #include <sys/random.h>
+#include <sys/syscall.h>
 
 #ifdef __NR_getrandom
 int