Support mprotect.

Change-Id: Ic786eb35f69d44379129faec02b1023ab2c3282a
diff --git a/ndk/sources/android/libportable/arch-mips/mmap.c b/ndk/sources/android/libportable/arch-mips/mmap.c
index 4f83bdb..d165e2b 100644
--- a/ndk/sources/android/libportable/arch-mips/mmap.c
+++ b/ndk/sources/android/libportable/arch-mips/mmap.c
@@ -85,3 +85,9 @@
 
     return ret;
 }
+
+extern int    mprotect(const void *, size_t, int);
+int mprotect_portable(const void *addr, size_t size, int prot)
+{
+    return mprotect(addr, size, mips_change_prot(prot));
+}