Fix for systems that don't build with gettext

src/main.cc

@@ -75,7 +75,9 @@ int main(int argc, char * argv[], char * envp[])
   std::signal(SIGINT, sigint_handler);
   std::signal(SIGPIPE, sigpipe_handler);
 
+#if defined(HAVE_GETTEXT)
   ::textdomain("ledger");
+#endif
 
   // Create the session object, which maintains nearly all state relating to
   // this invocation of Ledger; and register all known journal parsers.

src/system.hh

@@ -139,7 +139,6 @@ typedef std::ostream::pos_type ostream_pos_type;
 #include "gettext.h"
 #define _(str) gettext(str)
 #else
-#define textdomain(name)
 #define _(str) str
 #endif