Use different muparserx library in linux depending on the ABI (#561)

* Use different muparserx library in linux depending on the ABI supported by the compiler

* _C++_ var names to _CXX_ names. Remove old code. Add comments.

CMakeLists.txt

@@ -200,16 +200,8 @@ else()
 endif()
 
 message(STATUS "Uncompressing muparserx static library...")
-if(MSVC)
-	set(PLATFORM "win64")
-elseif(APPLE)
-	set(PLATFORM "macos")
-elseif(UNIX)
-	set(PLATFORM "linux")
-endif()
-execute_process(COMMAND ${CMAKE_COMMAND} -E tar "xvfj" "${AER_SIMULATOR_CPP_SRC_DIR}/third-party/${PLATFORM}/lib/muparserx.7z"
-	WORKING_DIRECTORY  "${AER_SIMULATOR_CPP_SRC_DIR}/third-party/${PLATFORM}/lib/")
-set(MUPARSERX_LIB_PATH "${AER_SIMULATOR_CPP_SRC_DIR}/third-party/${PLATFORM}/lib")
+
+uncompress_muparsersx_lib()
 
 find_library(MUPARSERX_LIB NAMES libmuparserx.a muparserx HINTS ${MUPARSERX_LIB_PATH})
 if(${MUPARSERX_LIB} MATCHES "MUPARSERX_LIB-NOTFOUND")

cmake/compiler_utils.cmake

@@ -56,4 +56,34 @@ function(get_muparserx_source_code)
                 Please download MuparserX library from https://github.com/beltoforion/muparserx.git \
                 and checkout latest stable release")
     endif()
-endfunction()
+endfunction()
+
+function(check_compiler_cpp11_abi)
+    # This is needed in case the compiler doesn't work with the new C++11 ABI,
+    # is the case of GCC in RHEL6 and RHEL7
+    # https://bugzilla.redhat.com/show_bug.cgi?id=1546704
+    # Consider also if -D_GLIBCXX_USE_CXX11_ABI has been passed as flag
+    string(REGEX MATCH "-D_GLIBCXX_USE_CXX11_ABI=[(A-z)|(a-z)|(0-9)]+" CUSTOM_PREP_FLAGS ${CMAKE_CXX_FLAGS})
+    # Preprocessor run to check if CXX11_ABI is set
+    execute_process(COMMAND echo "#include <string>" COMMAND ${CMAKE_CXX_COMPILER} ${CUSTOM_PREP_FLAGS} -x c++ -E -dM -  COMMAND fgrep _GLIBCXX_USE_CXX11_ABI OUTPUT_VARIABLE CXX11_ABI_OUT OUTPUT_STRIP_TRAILING_WHITESPACE)
+    string(REGEX REPLACE "#define _GLIBCXX_USE_CXX11_ABI " "" CXX11_ABI "${CXX11_ABI_OUT}")
+    set(CXX11_ABI ${CXX11_ABI} PARENT_SCOPE)
+endfunction()
+
+function(uncompress_muparsersx_lib)
+    if(MSVC)
+        set(PLATFORM "win64")
+    elseif(APPLE)
+        set(PLATFORM "macos")
+    elseif(UNIX)
+        check_compiler_cpp11_abi()
+        if(CXX11_ABI EQUAL "0")
+            set(MUPARSER_ABI_PREFIX oldabi_)
+        endif()
+        set(PLATFORM "linux")
+    endif()
+
+    execute_process(COMMAND ${CMAKE_COMMAND} -E tar "xvfj" "${AER_SIMULATOR_CPP_SRC_DIR}/third-party/${PLATFORM}/lib/${MUPARSER_ABI_PREFIX}muparserx.7z"
+            WORKING_DIRECTORY  "${AER_SIMULATOR_CPP_SRC_DIR}/third-party/${PLATFORM}/lib/")
+    set(MUPARSERX_LIB_PATH "${AER_SIMULATOR_CPP_SRC_DIR}/third-party/${PLATFORM}/lib" PARENT_SCOPE)
+endfunction()