my_db_strerror: Add missing dTHX declaration

[clayne]

• This function was missing a dTHX check (which is required with PERL_NO_GET_CONTEXT), but it wasn't visible unless TRACE was defined.

This fixes the following error:

BerkeleyDB.xs: In function ‘my_db_strerror’:
/usr/lib/perl5/5.26/x86_64-cygwin-threads/CORE/perl.h:176:16: error: ‘my_perl’ undeclared (first use in this function); did you mean ‘my_for’?
 #  define aTHX my_perl
                ^
/usr/lib/perl5/5.26/x86_64-cygwin-threads/CORE/perl.h:189:18: note: in expansion of macro ‘aTHX’
 #  define aTHX_  aTHX,
                  ^~~~
/usr/lib/perl5/5.26/x86_64-cygwin-threads/CORE/embed.h:178:34: note: in expansion of macro ‘aTHX_’
 #define get_sv(a,b)  Perl_get_sv(aTHX_ a,b)
                                  ^~~~~
/usr/lib/perl5/5.26/x86_64-cygwin-threads/CORE/embed.h:1932:29: note: in expansion of macro ‘get_sv’
 #  define perl_get_sv(a,b)  get_sv(a,b)
                             ^~~~~~
BerkeleyDB.xs:842:15: note: in expansion of macro ‘perl_get_sv’
     SV * sv = perl_get_sv(ERR_BUFF, FALSE) ;
               ^~~~~~~~~~~

[pmqs]

Thanks, good catch.

I'm seeing a lot of tests failing because of badly-formed trace messages. Need to sort that out before I merge the change.

[pmqs]

Change released in version 0.62