diff --git a/include/basetsd.h b/include/basetsd.h
index 81ada05ff5b..615b37197af 100644
--- a/include/basetsd.h
+++ b/include/basetsd.h
@@ -131,7 +131,7 @@ typedef ULONG_PTR SIZE_T, *PSIZE_T;
 # define WORDS_BIGENDIAN
 # define BITFIELDS_BIGENDIAN
 # undef  ALLOW_UNALIGNED_ACCESS
-#elif defined(__PPC__)
+#elif defined(__powerpc__)
 # define WORDS_BIGENDIAN
 # define BITFIELDS_BIGENDIAN
 # undef  ALLOW_UNALIGNED_ACCESS
diff --git a/include/rpc.h b/include/rpc.h
index c395132b7a3..aa7b0b760ec 100644
--- a/include/rpc.h
+++ b/include/rpc.h
@@ -25,8 +25,10 @@
 #ifndef __WINE_RPC_H
 #define __WINE_RPC_H
 
-#if defined(__PPC__) || defined(_MAC) /* ? */
+#if defined(__powerpc__) || defined(_MAC) /* ? */
  #define __RPC_MAC__
+ /* Also define __RPC_WIN32__ to ensure compatibility */
+ #define __RPC_WIN32__
 #elif defined(_WIN64)
  #define __RPC_WIN64__
 #else
diff --git a/include/winnt.h b/include/winnt.h
index 2592b694612..c79c6ad4a74 100644
--- a/include/winnt.h
+++ b/include/winnt.h
@@ -805,7 +805,7 @@ typedef struct _CONTEXT
 #endif  /* _MIPS_ */
 
 /* PowerPC context definitions */
-#ifdef __PPC__
+#ifdef __powerpc__
 
 #define CONTEXT_CONTROL         0x0001
 #define CONTEXT_FLOATING_POINT  0x0002
@@ -929,7 +929,7 @@ typedef struct _STACK_FRAME_HEADER
     DWORD Parameter7;
 } STACK_FRAME_HEADER,*PSTACK_FRAME_HEADER;
 
-#endif  /* __PPC__ */
+#endif  /* __powerpc__ */
 
 #ifdef __ALPHA__
 
@@ -1179,7 +1179,7 @@ static DWORD __builtin_return_address(int p_iDepth)
 
 #endif /* __sparc__ */
 
-#ifdef __PPC__
+#ifdef __powerpc__
 
 /* FIXME: use getcontext() to retrieve full context */
 #define _GET_CONTEXT \
@@ -1204,7 +1204,7 @@ static DWORD __builtin_return_address(int p_iDepth)
   void WINAPI name ( t1 a1, t2 a2, t3 a3, t4 a4 ) \
   { _GET_CONTEXT; fn( a1, a2, a3, a4, &context ); }
 
-#endif /* __PPC__ */
+#endif /* __powerpc__ */
 
 #ifdef __ALPHA__
 
@@ -1637,7 +1637,7 @@ extern inline struct _TEB * WINAPI NtCurrentTeb(void);
 extern inline struct _TEB * WINAPI NtCurrentTeb(void)
 {
     struct _TEB *teb;
-# ifdef __darwin__
+# ifdef __APPLE__
     __asm__("\tmr %0, r13" : "=r" (teb));
 # else
     __asm__("\tmr %0, 2" : "=r" (teb));