[lmi] [PATCH] Fixes for clang compilation

[Vadim Zeitlin]

 Hello,

 I've realize that I've apparently completely forgotten to post 2 patches
which are required to fix clang build that I did more than 2 weeks ago, so
please find them attached.

 The first one is similar to the other fixes after [[noreturn]] started to
be used and just moves it to the function declaration as otherwise clang
(correctly) complains about it being declared [[noreturn]] too late, e.g.

alert_cli.cpp:99:3: error: function declared '[[noreturn]]' after its first 
declaration
[[noreturn]]
  ^
alert.hpp:177:6: note: declaration missing '[[noreturn]]' attribute is here
void alarum_alert         (std::string const&);
     ^
1 error generated.
alert.cpp:270:3: error: function declared '[[noreturn]]' after its first 
declaration
[[noreturn]]
  ^
alert.hpp:246:13: note: declaration missing '[[noreturn]]' attribute is here
void LMI_SO test_standard_exception();
            ^
alert.cpp:276:3: error: function declared '[[noreturn]]' after its first 
declaration
[[noreturn]]
  ^
alert.hpp:247:13: note: declaration missing '[[noreturn]]' attribute is here
void LMI_SO test_arbitrary_exception();
            ^
2 errors generated.

 The other one fixes a warning given by clang for the unused private
fields. This one could be disabled instead of fixing it if there is some
really good reason to keep these fields or, on the contrary, extended in
order to remove the SequenceParser ctor arguments corresponding to them,
but for now I've just tried to make the minimal change allowing me to build
lmi with clang again.

 Thanks in advance for applying these patches,
VZ

0001-Use-noreturn-attribute-in-declarations-not-definitio.patch
Description: Text document

0002-Remove-unused-private-fields-of-SequenceParser-class.patch
Description: Text document