Fix android-16 compile.

CMakeLists.txt

@@ -65,8 +65,8 @@ if(NOT CMAKE_BUILD_TYPE)
 endif()
 
 if(ANDROID)
-    if(${CMAKE_SYSTEM_VERSION} VERSION_LESS "21")
+    if(${CMAKE_SYSTEM_VERSION} VERSION_LESS "16")
-        message(FATAL_ERROR "Unsupport standalone toolchains with Android API level lower than 21")
+        message(FATAL_ERROR "Unsupport standalone toolchains with Android API level lower than 16")
     endif()
 
     set(WITH_GPU OFF CACHE STRING

paddle/utils/Util.cpp

@@ -320,6 +320,9 @@ void loadFileList(const std::string& fileListFileName,
 }
 
 double getMemoryUsage() {
+#if defined(__ANDROID__)
+  return 0.0;
+#else
   FILE* fp = fopen("/proc/meminfo", "r");
   CHECK(fp) << "failed to fopen /proc/meminfo";
   size_t bufsize = 256 * sizeof(char);
@@ -357,6 +360,7 @@ double getMemoryUsage() {
   delete[] buf;
   double usedMem = 1.0 - 1.0 * (freeMem + bufMem + cacheMem) / totalMem;
   return usedMem;
+#endif
 }
 
 SyncThreadPool* getGlobalSyncThreadPool() {

paddle/utils/Util.h

@@ -33,6 +33,13 @@ limitations under the License. */
 #include "Flags.h"
 #include "hl_gpu.h"
 
+#if defined(__ANDROID__) && (__ANDROID_API__ < 21)
+inline int rand_r(unsigned int* seedp) {
+  (void)seedp;
+  return rand();
+}
+#endif
+
 /**
  * Loop over the elements in a container
  * TODO(yuyang18): It's this foreach useful? Why not use C++ 11 foreach,