diff --git a/framework/BuildDefines.h b/framework/BuildDefines.h
index cccf591..46740aa 100644
--- a/framework/BuildDefines.h
+++ b/framework/BuildDefines.h
@@ -60,11 +60,6 @@ If you have questions concerning this license or the applicable additional terms
 	#define ID_ALLOW_CHEATS 0
 #endif
 
-// fake a pure client. useful to connect an all-debug client to a server
-#ifndef ID_FAKE_PURE
-	#define ID_FAKE_PURE 0
-#endif
-
 // verify checksums in clientinfo traffic
 // NOTE: this makes the network protocol incompatible
 #ifndef ID_CLIENTINFO_TAGS
diff --git a/framework/FileSystem.h b/framework/FileSystem.h
index 5c0dc4f..f18441b 100644
--- a/framework/FileSystem.h
+++ b/framework/FileSystem.h
@@ -210,8 +210,6 @@ public:
 	virtual void			SetRestartChecksums( const int pureChecksums[ MAX_PURE_PAKS ] ) = 0;
 							// equivalent to calling SetPureServerChecksums with an empty list
 	virtual	void			ClearPureChecksums( void ) = 0;
-							// get a mask of supported OSes. if not pure, returns -1
-	virtual int				GetOSMask( void ) = 0;
 							// Reads a complete file.
 							// Returns the length of the file, or -1 on failure.
 							// A null buffer will just return the file length without loading.
diff --git a/sys/platform.h b/sys/platform.h
index 4998039..64aa5d2 100644
--- a/sys/platform.h
+++ b/sys/platform.h
@@ -43,8 +43,6 @@ If you have questions concerning this license or the applicable additional terms
 // Win32
 #if defined(WIN32) || defined(_WIN32)
 
-#define BUILD_OS_ID					0
-
 #define _alloca16( x )				((void *)((((uintptr_t)_alloca( (x)+15 )) + 15) & ~15))
 
 #define PATHSEPERATOR_STR			"\\"
@@ -80,8 +78,6 @@ If you have questions concerning this license or the applicable additional terms
 // Mac OSX
 #if defined(MACOS_X) || defined(__APPLE__)
 
-#define BUILD_OS_ID					1
-
 #ifdef GAME_DLL
 #define ID_GAME_API					__attribute__((visibility ("default")))
 #else
@@ -112,8 +108,6 @@ If you have questions concerning this license or the applicable additional terms
 // Unix
 #ifdef __unix__
 
-#define BUILD_OS_ID					2
-
 #define _alloca						alloca
 #define _alloca16( x )				((void *)((((uintptr_t)alloca( (x)+15 )) + 15) & ~15))