Added detection for clang compiler and fixed various warnings triggered by it (bug 4878, r=dvander).

core/LibrarySys.cpp

@@ -410,7 +410,7 @@ size_t LibrarySystem::GetFileFromPath(char *buffer, size_t maxlength, const char
 	size_t length = strlen(path);
 
 	for (size_t i = length - 1;
-		 i >= 0 && i <= length - 1;
+		 i <= length - 1;
 		 i--)
 	{
 		if (path[i] == '/' 

core/logic/TextParsers.cpp

@@ -872,7 +872,7 @@ bool TextParsers::ParseFile_INI(const char *file, ITextListener_INI *ini_listene
 		ptr = save_ptr;
 
 		/* Lastly, strip ending whitespace off */
-		for (size_t i=len-1; i>=0 && i<len; i--)
+		for (size_t i=len-1; i<len; i--)
 		{
 			if (g_ws_chartable[(unsigned char)ptr[i]])
 			{

core/sm_fastlink.h

@@ -37,7 +37,6 @@
 template <typename T>
 class FastLink
 {
-	friend class iterator;
 public:
 	struct FastLinkNode
 	{

core/sourcemod.cpp

@@ -142,7 +142,7 @@ bool SourceModBase::InitializeSourceMod(char *error, size_t maxlength, bool late
 
 	/* Store name of game directory by itself */
 	size_t len = strlen(gamepath);
-	for (size_t i = len - 1; i >= 0; i--)
+	for (size_t i = len - 1; i < len; i--)
 	{
 		if (gamepath[i] == PLATFORM_SEP_CHAR)
 		{