[cmake] Update top-level CMakeLists.txt file with latest app4triqs skeleton

Author: Wentzell

CMakeLists.txt

@@ -30,12 +30,17 @@ endif()
 project(cppdlr VERSION 1.0.0 LANGUAGES C CXX)
 get_directory_property(IS_SUBPROJECT PARENT_DIRECTORY)
 
-# Get the git hash & print status
-execute_process(COMMAND git rev-parse HEAD WORKING_DIRECTORY ${PROJECT_SOURCE_DIR} OUTPUT_VARIABLE PROJECT_GIT_HASH OUTPUT_STRIP_TRAILING_WHITESPACE)
+message(STATUS "-------- cppdlr version and git hash detection -------------")
+find_package(Git)
+execute_process(COMMAND ${GIT_EXECUTABLE} rev-parse HEAD
+  WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
+  OUTPUT_VARIABLE PROJECT_GIT_HASH
+  OUTPUT_STRIP_TRAILING_WHITESPACE
+)
 message(STATUS "${PROJECT_NAME} version : ${PROJECT_VERSION}")
 message(STATUS "${PROJECT_NAME} Git hash: ${PROJECT_GIT_HASH}")
 
-# Assert that Install directory is given and invalid.
+# Assert that install directory is provided and is absolute path.
 if(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT OR (NOT IS_ABSOLUTE ${CMAKE_INSTALL_PREFIX}))
   message(FATAL_ERROR "No install prefix given (or invalid)")
 endif()
@@ -115,7 +120,7 @@ target_compile_options(${PROJECT_NAME}_warnings
 # FIXME For future cmake versions we should populate the
 # INTERFACE_LINK_DIRECTORIES of the triqs target
 # ---------------------------------
-if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" AND DEFINED ENV{LIBRARY_PATH})
+if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND DEFINED ENV{LIBRARY_PATH})
   string(REPLACE ":" ";" LINK_DIRS $ENV{LIBRARY_PATH})
   foreach(dir ${LINK_DIRS})
     string(APPEND CMAKE_SHARED_LINKER_FLAGS " -L${dir}")
@@ -124,6 +129,9 @@ if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" AND DEFINED ENV{LIBRARY_PATH})
   endforeach()
 endif()
 
+# Provide GNU Installation directories
+include(GNUInstallDirs)
+
 # #############
 # Build Project