Revert "HADOOP-17196. Fix C/C++ standard warnings (#2208)"

This reverts commit b4a105a20981fda4ab60090e9ab3cef623b7df46.

hadoop-common-project/hadoop-common/HadoopCommon.cmake

@@ -193,7 +193,7 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
 elseif(CMAKE_SYSTEM_NAME STREQUAL "SunOS")
     # Solaris flags. 64-bit compilation is mandatory, and is checked earlier.
     hadoop_add_compiler_flags("-m64 -D_POSIX_C_SOURCE=200112L -D__EXTENSIONS__ -D_POSIX_PTHREAD_SEMANTICS")
-    set(CMAKE_CXX_STANDARD 98)
+    set(CMAKE_CXX_FLAGS "-std=gnu++98 ${CMAKE_CXX_FLAGS}")
     hadoop_add_linker_flags("-m64")
 
     # CMAKE_SYSTEM_PROCESSOR is set to the output of 'uname -p', which on Solaris is
@@ -212,4 +212,4 @@ elseif(CMAKE_SYSTEM_NAME STREQUAL "SunOS")
 endif()
 
 # Set GNU99 as the C standard to use
-set(CMAKE_C_STANDARD 99)
+set(CMAKE_C_FLAGS "-std=gnu99 ${CMAKE_C_FLAGS}")

hadoop-hdfs-project/hadoop-hdfs-native-client/src/CMakeLists.txt

@@ -153,8 +153,7 @@ add_subdirectory(main/native/libhdfs-examples)
 # Temporary fix to disable Libhdfs++ build on older systems that do not support thread_local
 include(CheckCXXSourceCompiles)
 unset (THREAD_LOCAL_SUPPORTED CACHE)
-set (CMAKE_CXX_STANDARD 11)
-set (CMAKE_CXX_STANDARD_REQUIRED ON)
+set (CMAKE_REQUIRED_DEFINITIONS "-std=c++11")
 set (CMAKE_REQUIRED_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
 check_cxx_source_compiles(
     "#include <thread>

hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/CMakeLists.txt

@@ -52,8 +52,7 @@ include(CheckSymbolExists)
 
 # Check if thread_local is supported
 unset (THREAD_LOCAL_SUPPORTED CACHE)
-set (CMAKE_CXX_STANDARD 11)
-set (CMAKE_CXX_STANDARD_REQUIRED ON)
+set (CMAKE_REQUIRED_DEFINITIONS "-std=c++11")
 set (CMAKE_REQUIRED_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
 check_cxx_source_compiles(
     "#include <thread>
@@ -154,13 +153,12 @@ set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -O0")
 set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -O0")
 
 if(UNIX)
-set (CMAKE_CXX_STANDARD 11)
-set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -pedantic -g -fPIC -fno-strict-aliasing")
+set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -pedantic -std=c++11 -g -fPIC -fno-strict-aliasing")
 set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g -fPIC -fno-strict-aliasing")
 endif()
 
 if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
-    set(CMAKE_CXX_STANDARD 11)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
     add_definitions(-DASIO_HAS_STD_ADDRESSOF -DASIO_HAS_STD_ARRAY -DASIO_HAS_STD_ATOMIC -DASIO_HAS_CSTDINT -DASIO_HAS_STD_SHARED_PTR -DASIO_HAS_STD_TYPE_TRAITS -DASIO_HAS_VARIADIC_TEMPLATES -DASIO_HAS_STD_FUNCTION -DASIO_HAS_STD_CHRONO -DASIO_HAS_STD_SYSTEM_ERROR)
 endif ()