Don't enable BFD if libiberty is not installed

CMakeLists.txt

@@ -202,10 +202,11 @@ if (ENABLE_BACKTRACE)
     endif()
     # Use GNU bfd if present.
     check_library_exists (bfd bfd_init ""  HAVE_BFD_LIB)
+    check_library_exists (iberty cplus_demangle "" HAVE_IBERTY_LIB)
     set(CMAKE_REQUIRED_DEFINITIONS -DPACKAGE=${PACKAGE} -DPACKAGE_VERSION=${PACKAGE_VERSION})
     check_include_file(bfd.h HAVE_BFD_H)
     set(CMAKE_REQUIRED_DEFINITIONS)
-    if (HAVE_BFD_LIB AND HAVE_BFD_H)
+    if (HAVE_BFD_LIB AND HAVE_BFD_H AND HAVE_IBERTY_LIB)
         set (HAVE_BFD True)
     endif()
 endif()