diff --git a/linux_sdk/Makefile b/linux_sdk/Makefile
index 30c14ab6..88fcd42c 100644
--- a/linux_sdk/Makefile
+++ b/linux_sdk/Makefile
@@ -32,9 +32,9 @@ CPLUS = /usr/bin/clang++
 CLINK = /usr/bin/clang
 CPP_LIB =
 else
-CC = /usr/bin/gcc
-CPLUS = /usr/bin/g++
-CLINK = /usr/bin/gcc
+CC = /usr/bin/clang
+CPLUS = /usr/bin/clang++
+CLINK = /usr/bin/clang
 CPP_LIB = $(SRCDS_DIR)/bin/libstdc++.so.6
 endif
 
@@ -96,7 +96,7 @@ DEFINES +=-DGNUC -DPOSIX -D_POSIX -DVPROF_LEVEL=1 -DSWDS -D_finite=finite -Dstri
 UNDEF = -Usprintf -Ustrncpy -UPROTECTED_THINGS_ENABLE
 
 BASE_CFLAGS = -fno-strict-aliasing -Wall -Wsign-compare -Werror -Wno-conversion -Wno-overloaded-virtual -Wno-non-virtual-dtor -Wno-invalid-offsetof \
-	      -Wno-delete-non-virtual-dtor
+	      -Wno-delete-non-virtual-dtor -Wno-deprecated-register
 SHLIBCFLAGS = -fPIC
 
 # Flags passed to the c compiler
diff --git a/public/tier0/threadtools.h b/public/tier0/threadtools.h
index 3b0e4710..442459b5 100644
--- a/public/tier0/threadtools.h
+++ b/public/tier0/threadtools.h
@@ -983,7 +983,12 @@ private:
 class TFRWL_ALIGN TT_CLASS CThreadSpinRWLock
 {
 public:
-	CThreadSpinRWLock()	{ COMPILE_TIME_ASSERT( sizeof( LockInfo_t ) == sizeof( int64 ) ); Assert( (int)this % 8 == 0 ); memset( this, 0, sizeof( *this ) ); }
+	CThreadSpinRWLock()	{
+		COMPILE_TIME_ASSERT( sizeof( LockInfo_t ) == sizeof( int64 ) );
+		Assert( (intp)this % 8 == 0 );
+		m_lockInfo.m_writerId = 0;
+		m_lockInfo.m_nReaders = 0;
+	}
 
 	bool TryLockForWrite();
 	bool TryLockForRead();
diff --git a/public/tier1/utlmemory.h b/public/tier1/utlmemory.h
index 5b0c8ffb..6ccc775f 100644
--- a/public/tier1/utlmemory.h
+++ b/public/tier1/utlmemory.h
@@ -1,4 +1,4 @@
-//===== Copyright © 1996-2005, Valve Corporation, All rights reserved. ======//
+//===== Copyright � 1996-2005, Valve Corporation, All rights reserved. ======//
 //
 // Purpose: 
 //
@@ -17,6 +17,7 @@
 #include "tier0/dbg.h"
 #include <string.h>
 #include "tier0/platform.h"
+#include "mathlib/mathlib.h"
 
 #include "tier0/memalloc.h"
 #include "tier0/memdbgon.h"
diff --git a/tier1/bitbuf.cpp b/tier1/bitbuf.cpp
index f49f5ea0..fbaf4e86 100644
--- a/tier1/bitbuf.cpp
+++ b/tier1/bitbuf.cpp
@@ -867,7 +867,9 @@ int old_bf_read::ReadSBitLong( int numbits )
 }
 
 const byte g_BitMask[8] = {0x1, 0x2, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80};
+#if FAST_BIT_SCAN
 const byte g_TrailingMask[8] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80};
+#endif
 
 inline int old_bf_read::CountRunOfZeros()
 {