add lower version cmake support

CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 PROJECT(TDengine)
 
 SET(CMAKE_C_STANDARD 11)
@@ -20,7 +20,7 @@ IF (${CMAKE_SYSTEM_NAME} MATCHES "Linux" OR UNIX)
 ENDIF ()
 
 #set debug & release related options
-SET(COMMON_FLAGS "-Wall -fPIC -malign-double -Wno-char-subscripts -malign-stringops -msse4.2 -D_FILE_OFFSET_BITS=64 -D_LARGE_FILE")
+SET(COMMON_FLAGS "-std=gnu99 -Wall -fPIC -malign-double -Wno-char-subscripts -malign-stringops -msse4.2 -D_FILE_OFFSET_BITS=64 -D_LARGE_FILE")
 SET(COMMON_CXX_FLAGS "${COMMON_FLAGS} -std=c++11")
 SET(DEBUG_FLAGS "-O0 -DDEBUG")
 
@@ -43,7 +43,7 @@ ENDIF ()
 #set output directory
 SET(LIBRARY_OUTPUT_PATH ${PROJECT_BINARY_DIR}/build/lib)
 SET(EXECUTABLE_OUTPUT_PATH ${PROJECT_BINARY_DIR}/build/bin)
-SET(TESTS_OUTPUT_DIR ${PROJECT_BINARY_DIR}/build/test)
+SET(TESTS_OUTPUT_DIR ${PROJECT_BINARY_DIR}/test)
 
 MESSAGE(STATUS "Project binary output path: " ${PROJECT_BINARY_DIR})
 MESSAGE(STATUS "Executable files output path: " ${EXECUTABLE_OUTPUT_PATH})

README.md

@@ -23,7 +23,7 @@ Refer to [TDengine Documentation](https://www.taosdata.com/en/documentation/)
 # Building
 At the moment, TDengine only supports building and running on Linux systems. You can choose to [install from packages](https://www.taosdata.com/en/getting-started/#Install-from-Package) or from the source code. This quick guide is for installation from the source only.
 
-To build TDengine, use [CMake](https://cmake.org/) 3.5 or higher versions in the project directory:
+To build TDengine, use [CMake](https://cmake.org/) 2.8 or higher versions in the project directory:
 
 ```cmd
 mkdir build && cd build

deps/CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 PROJECT(TDengine)
 

deps/zlib-1.2.11/CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 PROJECT(TDengine)
 

src/CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 PROJECT(TDengine)
 

src/client/CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 PROJECT(TDengine)
 

src/connector/jdbc/CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 PROJECT(TDengine)
 

src/kit/shell/CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 PROJECT(TDengine)
 

src/kit/taosBenchmark/CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 PROJECT(TDengine)
 

src/kit/taosdump/CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 PROJECT(TDengine)
 

src/modules/http/CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 PROJECT(TDengine)
 

src/modules/monitor/CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 PROJECT(TDengine)
 

src/rpc/CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 PROJECT(TDengine)
 

src/sdb/CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 PROJECT(TDengine)
 

src/system/CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 PROJECT(TDengine)
 
@@ -12,6 +12,8 @@ SET(PREPARE_ENV_CMD "prepare_env_cmd")
 SET(PREPARE_ENV_TARGET "prepare_env_target")
 ADD_CUSTOM_COMMAND(OUTPUT ${PREPARE_ENV_CMD}
   POST_BUILD 
+  COMMAND echo "make test directory"
+  DEPENDS taosd
   COMMAND ${CMAKE_COMMAND} -E make_directory ${TESTS_OUTPUT_DIR}/cfg/
   COMMAND ${CMAKE_COMMAND} -E make_directory ${TESTS_OUTPUT_DIR}/log/
   COMMAND ${CMAKE_COMMAND} -E make_directory ${TESTS_OUTPUT_DIR}/data/

src/util/CMakeLists.txt

-CMAKE_MINIMUM_REQUIRED(VERSION 3.5)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 PROJECT(TDengine)