ndk: <pthread.h>: formatting + updates

This patch improves the formatting of <pthread.h> as exposed by the NDK:

- change '#if __cplusplus' into '#ifdef __cplusplus'
- change C++-style comment into C-style comment

Change-Id: Ib093058e8d7a7554d8329a40e102cde11d065932
diff --git a/ndk/platforms/android-3/include/pthread.h b/ndk/platforms/android-3/include/pthread.h
index e3afdae..2a6029d 100644
--- a/ndk/platforms/android-3/include/pthread.h
+++ b/ndk/platforms/android-3/include/pthread.h
@@ -103,7 +103,7 @@
 /*
  * Prototypes
  */
-#if __cplusplus
+#ifdef __cplusplus
 extern "C" {
 #endif
 
@@ -231,7 +231,7 @@
         __pthread_cleanup_pop( &__cleanup, (execute)); \
     } while (0);
 
-#if __cplusplus
+#ifdef __cplusplus
 } /* extern "C" */
 #endif
 
@@ -240,4 +240,4 @@
 #define LONG_LONG_MAX __LONG_LONG_MAX__
 #define LONG_LONG_MIN (-__LONG_LONG_MAX__ - 1)
 
-#endif // _PTHREAD_H_
+#endif /* _PTHREAD_H_ */
diff --git a/ndk/platforms/android-5/include/pthread.h b/ndk/platforms/android-5/include/pthread.h
index 6603b3f..a20a52d 100644
--- a/ndk/platforms/android-5/include/pthread.h
+++ b/ndk/platforms/android-5/include/pthread.h
@@ -103,7 +103,7 @@
 /*
  * Prototypes
  */
-#if __cplusplus
+#ifdef __cplusplus
 extern "C" {
 #endif
 
@@ -258,7 +258,7 @@
         __pthread_cleanup_pop( &__cleanup, (execute)); \
     } while (0);
 
-#if __cplusplus
+#ifdef __cplusplus
 } /* extern "C" */
 #endif
 
@@ -267,4 +267,4 @@
 #define LONG_LONG_MAX __LONG_LONG_MAX__
 #define LONG_LONG_MIN (-__LONG_LONG_MAX__ - 1)
 
-#endif // _PTHREAD_H_
+#endif /* _PTHREAD_H_ */
diff --git a/ndk/platforms/android-8/include/pthread.h b/ndk/platforms/android-8/include/pthread.h
index eb2d169..f7a596a 100644
--- a/ndk/platforms/android-8/include/pthread.h
+++ b/ndk/platforms/android-8/include/pthread.h
@@ -103,7 +103,7 @@
 /*
  * Prototypes
  */
-#if __cplusplus
+#ifdef __cplusplus
 extern "C" {
 #endif
 
@@ -263,7 +263,7 @@
         __pthread_cleanup_pop( &__cleanup, (execute)); \
     } while (0);
 
-#if __cplusplus
+#ifdef __cplusplus
 } /* extern "C" */
 #endif
 
@@ -272,4 +272,4 @@
 #define LONG_LONG_MAX __LONG_LONG_MAX__
 #define LONG_LONG_MIN (-__LONG_LONG_MAX__ - 1)
 
-#endif // _PTHREAD_H_
+#endif /* _PTHREAD_H_ */
diff --git a/ndk/platforms/android-9/include/pthread.h b/ndk/platforms/android-9/include/pthread.h
index 5e87043..4baf82f 100644
--- a/ndk/platforms/android-9/include/pthread.h
+++ b/ndk/platforms/android-9/include/pthread.h
@@ -103,7 +103,7 @@
 /*
  * Prototypes
  */
-#if __cplusplus
+#ifdef __cplusplus
 extern "C" {
 #endif
 
@@ -302,7 +302,7 @@
         __pthread_cleanup_pop( &__cleanup, (execute)); \
     } while (0);
 
-#if __cplusplus
+#ifdef __cplusplus
 } /* extern "C" */
 #endif
 
@@ -311,4 +311,4 @@
 #define LONG_LONG_MAX __LONG_LONG_MAX__
 #define LONG_LONG_MIN (-__LONG_LONG_MAX__ - 1)
 
-#endif // _PTHREAD_H_
+#endif /* _PTHREAD_H_ */