Fix build for UCLIBC platforms

tests/VarAllocTest.cpp

 #include "Test.h"
 #include "SkVarAlloc.h"
 
 DEF_TEST(VarAlloc, r) {
     SkVarAlloc va(4/*start allocating at 16B*/);
     char* p = va.alloc(128, SK_MALLOC_THROW);
     sk_bzero(p, 128);  // Just checking this is safe.
 
-#ifndef SK_BUILD_FOR_ANDROID
-    // This method will always return 0 on Android.
+#if !defined(SK_BUILD_FOR_ANDROID) && !defined(__UCLIBC__)
+    // This method will always return 0 on Android and UCLIBC platforms.
     REPORTER_ASSERT(r, va.approxBytesAllocated() >= 128);
 #endif
 }