minimal plan9port to cross-build Jehanne

lib/lib9/mallocz.c

@@ -0,0 +1,15 @@
+#include <u.h>
+#include <unistd.h>
+#include <string.h>
+#include <libc.h>
+
+void*
+mallocz(unsigned long n, int clr)
+{
+	void *v;
+
+	v = malloc(n);
+	if(clr && v)
+		memset(v, 0, n);
+	return v;
+}