Fixed a ton of gcc compile warnings

Removed some unused variables, added some consts, changed some casts
to const_cast. I don't think any of these changes are very
controversial.

Differential Revision: http://reviews.llvm.org/D9674

llvm-svn: 237218
diff --git a/lldb/source/Symbol/Symtab.cpp b/lldb/source/Symbol/Symtab.cpp
index 96622d7..dc69525 100644
--- a/lldb/source/Symbol/Symtab.cpp
+++ b/lldb/source/Symbol/Symtab.cpp
@@ -210,8 +210,8 @@
 static int
 CompareSymbolID (const void *key, const void *p)
 {
-    const user_id_t match_uid = *(user_id_t*) key;
-    const user_id_t symbol_uid = ((Symbol *)p)->GetID();
+    const user_id_t match_uid = *(const user_id_t*) key;
+    const user_id_t symbol_uid = ((const Symbol *)p)->GetID();
     if (match_uid < symbol_uid)
         return -1;
     if (match_uid > symbol_uid)
@@ -227,7 +227,7 @@
     Symbol *symbol = (Symbol*)::bsearch (&symbol_uid, 
                                          &m_symbols[0], 
                                          m_symbols.size(), 
-                                         (uint8_t *)&m_symbols[1] - (uint8_t *)&m_symbols[0], 
+                                         sizeof(m_symbols[0]),
                                          CompareSymbolID);
     return symbol;
 }