Fix OpenBSD linker warnings

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5044 c046a42c-6fe2-441c-8c8c-71466251a162
diff --git a/qemu-malloc.c b/qemu-malloc.c
index 606eda6..8ad6168 100644
--- a/qemu-malloc.c
+++ b/qemu-malloc.c
@@ -56,9 +56,10 @@
 char *qemu_strdup(const char *str)
 {
     char *ptr;
-    ptr = qemu_malloc(strlen(str) + 1);
+    size_t len = strlen(str);
+    ptr = qemu_malloc(len + 1);
     if (!ptr)
         return NULL;
-    strcpy(ptr, str);
+    pstrcpy(ptr, len, str);
     return ptr;
 }