some strict cxx98 check

src/utils/thread.h

@@ -55,8 +55,10 @@ inline void ThreadExit(void *status) {
 }  // namespace xgboost
 #else
 // thread interface using g++     
+extern "C" {
 #include <semaphore.h>
 #include <pthread.h>
+}
 namespace xgboost {
 namespace utils {
 /*!\brief semaphore class */
@@ -120,6 +122,7 @@ class Semaphore {
   }
   #endif  
 };
+
 /*!\brief simple thread class */
 class Thread {
  private:
@@ -130,7 +133,7 @@ class Thread {
     pthread_attr_init(&attr);
     pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
     pthread_create(&thread, &attr, entry, param);
-  }  
+  }
   inline int Join(void) {
     void *status;
     return pthread_join(thread, &status);

src/utils/thread_buffer.h

@@ -31,7 +31,8 @@ class ThreadBuffer {
   }
   /*!\brief set parameter, will also pass the parameter to factory */
   inline void SetParam(const char *name, const char *val) {
-    if (!std::strcmp( name, "buffer_size")) buf_size = atoi(val);
+    using namespace std;
+    if (!strcmp( name, "buffer_size")) buf_size = atoi(val);
     factory.SetParam(name, val);
   }
   /*!