Improve cmake timestamp and git csv retrieval to avoid useless rebuild

- Before, visp-build-info.tmp was modified after each call to cmake leading
  to rebuilding vpIoTools.cpp and thus visp_core...
- Now visp-build-info.tmp is updated only if necessary
- This commit removes also all specific cmake code when cmake < 2.8.12

CMakeLists.txt

@@ -1262,16 +1262,7 @@ vp_system_information(NUMBER_OF_LOGICAL_CORES NUMBER_OF_PHYSICAL_CORES TOTAL_PHY
 find_host_package(Git QUIET)
 
 if(NOT DEFINED VISP_VCSVERSION AND GIT_FOUND)
-  execute_process(COMMAND "${GIT_EXECUTABLE}" describe --tags --always --dirty --match "v[0-9].[0-9].[0-9]*"
-    WORKING_DIRECTORY "${VISP_SOURCE_DIR}"
-    OUTPUT_VARIABLE VISP_VCSVERSION
-    RESULT_VARIABLE GIT_RESULT
-    ERROR_QUIET
-    OUTPUT_STRIP_TRAILING_WHITESPACE
-  )
-  if(NOT GIT_RESULT EQUAL 0)
-    set(VISP_VCSVERSION "unknown")
-  endif()
+  vp_git_describe(VISP_VCSVERSION "${VISP_SOURCE_DIR}")
 elseif(NOT DEFINED VISP_VCSVERSION)
   # We don't have git:
   set(VISP_VCSVERSION "unknown")
@@ -1322,11 +1313,12 @@ endif()
 # ========================== build platform ==========================
 status("")
 status("  Platform:")
-if(NOT CMAKE_VERSION VERSION_LESS 2.8.11)
-  string(TIMESTAMP TIMESTAMP "" UTC)
-  if(TIMESTAMP)
-    status("    Timestamp:"    ${TIMESTAMP})
-  endif()
+if(NOT DEFINED VISP_TIMESTAMP AND NOT BUILD_INFO_SKIP_TIMESTAMP)
+  string(TIMESTAMP VISP_TIMESTAMP "" UTC)
+  set(VISP_TIMESTAMP "${VISP_TIMESTAMP}" CACHE STRING "Timestamp of ViSP build configuration" FORCE)
+endif()
+if(VISP_TIMESTAMP)
+  status("    Timestamp:"      ${VISP_TIMESTAMP})
 endif()
 status("    Host:"             ${CMAKE_HOST_SYSTEM_NAME} ${CMAKE_HOST_SYSTEM_VERSION} ${CMAKE_HOST_SYSTEM_PROCESSOR})
 if(CMAKE_CROSSCOMPILING)

cmake/VISPModule.cmake

@@ -590,11 +590,6 @@ macro(vp_target_include_modules target)
     if(d MATCHES "^visp_" AND HAVE_${d})
       if (EXISTS "${VISP_MODULE_${d}_LOCATION}/include")
         vp_target_include_directories(${target} "${VISP_MODULE_${d}_LOCATION}/include")
-        # Work around to be able to build the modules without INTERFACE_INCLUDE_DIRECTORIES
-        # that was only introduces since CMake 2.8.12
-        if (CMAKE_VERSION VERSION_LESS 2.8.12)
-          vp_target_include_directories(${target} "${VISP_MODULE_${d}_INC_DEPS}")
-        endif()
       endif()
     elseif(EXISTS "${d}")
       # FS keep external deps inc
@@ -992,11 +987,6 @@ macro(vp_add_tests)
     foreach(d ${VISP_TEST_${the_module}_DEPS})
       list(APPEND test_deps ${d})
       list(APPEND test_deps ${VISP_MODULE_${d}_DEPS})
-      # Work around to be able to build the modules without INTERFACE_INCLUDE_DIRECTORIES
-      # that was only introduces since CMake 2.8.12
-      if(CMAKE_VERSION VERSION_LESS 2.8.12)
-        list(APPEND test_deps "${VISP_MODULE_${__m}_INC_DEPS}")
-      endif()
     endforeach()
 
     vp_check_dependencies(${test_deps})

cmake/VISPUtils.cmake

@@ -195,15 +195,11 @@ function(vp_target_include_directories target)
     endif()
   endforeach()
   if(__params)
-    if(CMAKE_VERSION VERSION_LESS 2.8.11)
-      include_directories(${__params})
+    if(TARGET ${target})
+      target_include_directories(${target} PRIVATE ${__params})
     else()
-      if(TARGET ${target})
-        target_include_directories(${target} PRIVATE ${__params})
-      else()
-        set(__new_inc "${VP_TARGET_INCLUDE_DIRS_${target}};${__params}")
-        set(VP_TARGET_INCLUDE_DIRS_${target} "${__new_inc}" CACHE INTERNAL "")
-      endif()
+      set(__new_inc "${VP_TARGET_INCLUDE_DIRS_${target}};${__params}")
+      set(VP_TARGET_INCLUDE_DIRS_${target} "${__new_inc}" CACHE INTERNAL "")
     endif()
   endif()
 endfunction()
@@ -1969,3 +1965,26 @@ macro(vp_list_replace_string list_in list_out regular_expression replacement_exp
   endforeach()
   set(${list_out} ${__list_out})
 endmacro()
+
+macro(vp_git_describe var_name path)
+  if(GIT_FOUND)
+    execute_process(COMMAND "${GIT_EXECUTABLE}" describe --tags --exact-match --dirty
+      WORKING_DIRECTORY "${path}"
+      OUTPUT_VARIABLE ${var_name}
+      RESULT_VARIABLE GIT_RESULT
+      ERROR_QUIET
+      OUTPUT_STRIP_TRAILING_WHITESPACE
+    )
+    if(NOT GIT_RESULT EQUAL 0)
+      execute_process(COMMAND "${GIT_EXECUTABLE}" describe --tags --always --dirty --match "[0-9].[0-9].[0-9]*"
+        WORKING_DIRECTORY "${path}"
+        OUTPUT_VARIABLE ${var_name}
+        RESULT_VARIABLE GIT_RESULT
+        ERROR_QUIET
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+      )
+    endif()
+  else()
+    set(${var_name} "unknown")
+  endif()
+endmacro()

platforms/android/android.toolchain.cmake

@@ -1156,9 +1156,6 @@ if( NOT CMAKE_C_COMPILER )
 endif()
 
 set( _CMAKE_TOOLCHAIN_PREFIX "${ANDROID_TOOLCHAIN_MACHINE_NAME}-" )
-if( CMAKE_VERSION VERSION_LESS 2.8.5 )
- set( CMAKE_ASM_COMPILER_ARG1 "-c" )
-endif()
 if( APPLE )
  find_program( CMAKE_INSTALL_NAME_TOOL NAMES install_name_tool )
  if( NOT CMAKE_INSTALL_NAME_TOOL )