Backtrace stuff ahoy!

* Properly detect and utilize libdl.
* Set the backtrace method appropriately.
* Remove an unused backtrace format. No references existed.

StepmaniaCore.cmake

@@ -342,12 +342,7 @@ elseif(LINUX)
     message(FATAL_ERROR "jpeg support required.")
   endif()
 
-  find_library(DL_LIBRARY dl)
+  find_package(Dl)
-  if(${LIBDL_FOUND})
-    set(HAS_LIBDL TRUE)
-  else()
-    set(HAS_LIBDL FALSE)
-  endif()
 
   find_package(Xrandr)
   if (${XRANDR_FOUND})

src/CMakeLists.txt

@@ -280,6 +280,11 @@ else() # Linux
       sm_add_compile_definition("${SM_EXE_NAME}" BACKTRACE_METHOD_X86_LINUX)
       sm_add_compile_definition("${SM_EXE_NAME}" BACKTRACE_METHOD_TEXT="x86 custom backtrace")
       sm_add_compile_definition("${SM_EXE_NAME}" BACKTRACE_LOOKUP_METHOD_TEXT="backtrace_symbols")
+      if (${DL_FOUND})
+        sm_add_compile_definition("${SM_EXE_NAME}" BACKTRACE_LOOKUP_METHOD_DLADDR)
+      else()
+        sm_add_compile_definition("${SM_EXE_NAME}" BACKTRACE_LOOKUP_METHOD_BACKTRACE_SYMBOLS)
+      endif()
     endif()
   endif()
   if (${HAS_PTHREAD})
@@ -440,9 +445,9 @@ else() # Unix / Linux
     endif()
   endif()
 
-  list(APPEND SMDATA_LINK_LIB
+  if (${DL_FOUND})
-    "${DL_LIBRARY}"
+    list(APPEND SMDATA_LINK_LIB ${DL_LIBRARIES})
-  )
+  endif()
 
   if(HAS_OGG)
     list(APPEND SMDATA_LINK_LIB
@@ -557,6 +562,9 @@ if(NOT APPLE)
     if (PCRE_FOUND)
       list(APPEND SM_INCLUDE_DIRS "${PCRE_INCLUDE_DIR}")
     endif()
+    if (DL_FOUND)
+      list(APPEND SM_INCLUDE_DIRS "${DL_INCLUDE_DIR}")
+    endif()
   endif()
 else()
   if(WITH_OGG)

src/archutils/Unix/BacktraceNames.cpp

@@ -340,117 +340,6 @@ void BacktraceNames::FromString( RString s )
         }
     }
 }
-#elif defined(BACKTRACE_LOOKUP_METHOD_ATOS)
-void BacktraceNames::FromAddr( const void *p )
-{
-    int fds[2];
-    pid_t pid;
-    pid_t ppid = getpid(); /* Do this before fork()ing! */
-    
-    Offset = 0;
-    Address = intptr_t(p);
-
-    if (pipe(fds) != 0)
-    {
-        fprintf(stderr, "FromAddr pipe() failed: %s\n", strerror(errno));
-        return;
-    }
-
-    pid = fork();
-    if (pid == -1)
-    {
-        fprintf(stderr, "FromAddr fork() failed: %s\n", strerror(errno));
-        return;
-    }
-
-    if (pid == 0)
-    {
-        close(fds[0]);
-        for (int fd = 3; fd < 1024; ++fd)
-            if (fd != fds[1])
-                close(fd);
-        dup2(fds[1], fileno(stdout));
-        close(fds[1]);
-
-        char *addy;
-        asprintf(&addy, "0x%x", long(p));
-        char *p;
-        asprintf(&p, "%d", ppid);
-
-        execl("/usr/bin/atos", "/usr/bin/atos", "-p", p, addy, NULL);
-        
-        fprintf(stderr, "execl(atos) failed: %s\n", strerror(errno));
-        free(addy);
-        free(p);
-        _exit(1);
-    }
-    
-    close(fds[1]);
-    char f[1024];
-    bzero(f, 1024);
-    int len = read(fds[0], f, 1024);
-
-    Symbol = "";
-    File = "";
-
-    if (len == -1)
-    {
-        fprintf(stderr, "FromAddr read() failed: %s\n", strerror(errno));
-        return;
-    }
-    vector<RString> mangledAndFile;
-
-    split(f, " ", mangledAndFile, true);
-    if (mangledAndFile.size() == 0)
-        return;
-    Symbol = mangledAndFile[0];
-    /* eg
-     * -[NSApplication run]
-     * +[SomeClass initialize]
-     */
-    if (Symbol[0] == '-' || Symbol[0] == '+')
-    {
-        Symbol = mangledAndFile[0] + " " + mangledAndFile[1];
-        /* eg
-         * (crt.c:300)
-         * (AppKit)
-         */
-        if (mangledAndFile.size() == 3)
-        {
-            File = mangledAndFile[2];
-            size_t pos = File.find('(');
-            size_t start = (pos == File.npos ? 0 : pos+1);
-            pos = File.rfind(')') - 1;
-            File = File.substr(start, pos);
-        }
-        return;
-    }
-    /* eg
-     * __start   -> _start
-     * _SDL_main -> SDL_main
-     */
-    if (Symbol[0] == '_')
-        Symbol = Symbol.substr(1);
-    
-    /* eg, the full line:
-     * __Z1Ci (in a.out) (asmtest.cc:33)
-     * _main (in a.out) (asmtest.cc:52)
-     */
-    if (mangledAndFile.size() > 3)
-    {
-        File = mangledAndFile[3];
-        size_t pos = File.find('(');
-        size_t start = (pos == File.npos ? 0 : pos+1);
-        pos = File.rfind(')') - 1;
-        File = File.substr(start, pos);
-    }
-    /* eg, the full line:
-     * _main (SDLMain.m:308)
-     * __Z8GameLoopv (crt.c:300)
-     */
-    else if (mangledAndFile.size() == 3)
-        File = mangledAndFile[2].substr(0, mangledAndFile[2].rfind(')'));
-}
 #else
 #warning Undefined BACKTRACE_LOOKUP_METHOD_*
 void BacktraceNames::FromAddr( const void *p )