It doesn't do any good to define signals that a system doesn't have ...

stepmania/configure.ac

@@ -63,16 +63,7 @@ AH_VERBATIM([VA_ZZZ_NEEDED_FUNCS],
 #endif
 ])
 
-AC_CHECK_DECLS([SIGPWR, SIGUSR1],,,[#include <signal.h>])
-AH_VERBATIM([SIGNALS],
-[#if !HAVE_DECL_SIGPWR
-#if HAVE_DECL_SIGUSR1
-#define SIGPWR SIGUSR1
-#else  //!HAVE_DECL_SIGUSR1
-#define SIGPWR 30
-#endif //HAVE_DECL_SIGUSR1
-#endif //!HAVE_DECL_SIGPWR
-])
+AC_CHECK_DECLS([SIGPWR],,,[#include <signal.h>])
 
 case $host in
 	*-*-darwin*)

stepmania/src/archutils/Unix/SignalHandler.cpp

@@ -11,7 +11,10 @@ static bool initted = false;
 
 static int signals[] = {
 	SIGALRM, SIGBUS, SIGFPE, SIGHUP, SIGILL, SIGINT, SIGIOT, SIGPIPE,
-	SIGPWR, SIGQUIT, SIGSEGV, SIGTRAP, SIGTERM, SIGVTALRM, SIGXCPU, SIGXFSZ,
+	SIGQUIT, SIGSEGV, SIGTRAP, SIGTERM, SIGVTALRM, SIGXCPU, SIGXFSZ,
+#if defined(HAVE_DECL_SIGPWR)
+	SIGPWR,
+#endif
 	-1
 };