[gdb/build] Fix unused var in corelow.c

On x86_64-linux, with gcc 7.5.0 and CFLAGS/CXXFLAGS="-O0 -g -Wall" I ran into
a build breaker:
...
gdb/corelow.c: In member function ‘void mapped_file_info::add(const char*, const char*, const char*, std::vector<mem_range>&&, const bfd_build_id*)’:
gdb/corelow.c:1822:27: error: unused variable ‘it’ [-Werror=unused-variable]
   const auto [it, inserted]
                           ^
...

Fix this by dropping the variable it.

Tested on x86_64-linux.

Reviewed-By: Lancelot Six<lancelot.six@amd.com>

diff --git a/gdb/corelow.c b/gdb/corelow.c
index 16f07c23faa058dade9f6491512412cd8f59595f..ab2fa746de8e5f51d76bf48fa739215660b3901c 100644 (file)
--- a/gdb/corelow.c
+++ b/gdb/corelow.c
@@ -1819,8 +1819,8 @@ mapped_file_info::add (const char *soname,
      parsed, we group the build-id information based on the file name.  As
      a consequence, we should see each EXPECTED_FILENAME value exactly
      once.  This means that each insertion should always succeed.  */
-  const auto [it, inserted]
-    = m_filename_to_build_id_map.emplace (expected_filename, build_id);
+  const auto inserted
+    = m_filename_to_build_id_map.emplace (expected_filename, build_id).second;
   gdb_assert (inserted);
 
   /* Setup the reverse build-id to file name map.  */