11 files changed, 42 insertions, 4 deletions
diff --git a/Include/internal/pycore_blocks_output_buffer.h b/Include/internal/pycore_blocks_output_buffer.h
index 28cf6fb..573e103 100644
--- a/Include/internal/pycore_blocks_output_buffer.h
+++ b/Include/internal/pycore_blocks_output_buffer.h
@@ -40,6 +40,10 @@ extern "C" {
 
 #include "Python.h"
 
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
+
 typedef struct {
     // List of bytes objects
     PyObject *list;
@@ -314,4 +318,4 @@ _BlocksOutputBuffer_OnError(_BlocksOutputBuffer *buffer)
 #ifdef __cplusplus
 }
 #endif
-#endif /* Py_INTERNAL_BLOCKS_OUTPUT_BUFFER_H */
-\ No newline at end of file
+#endif /* Py_INTERNAL_BLOCKS_OUTPUT_BUFFER_H */
diff --git a/Include/internal/pycore_code.h b/Include/internal/pycore_code.h
index 0009937..f5127a8 100644
--- a/Include/internal/pycore_code.h
+++ b/Include/internal/pycore_code.h
@@ -4,6 +4,10 @@
 extern "C" {
 #endif
 
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
+
 #define CODE_MAX_WATCHERS 8
 
 /* PEP 659
diff --git a/Include/internal/pycore_codecs.h b/Include/internal/pycore_codecs.h
index a246519..a2a7151 100644
--- a/Include/internal/pycore_codecs.h
+++ b/Include/internal/pycore_codecs.h
@@ -4,6 +4,10 @@
 extern "C" {
 #endif
 
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
+
 extern PyObject* _PyCodec_Lookup(const char *encoding);
 
 /* Text codec specific encoding and decoding API.
diff --git a/Include/internal/pycore_emscripten_signal.h b/Include/internal/pycore_emscripten_signal.h
index 8b3287d..d1bcb9a 100644
--- a/Include/internal/pycore_emscripten_signal.h
+++ b/Include/internal/pycore_emscripten_signal.h
@@ -3,6 +3,10 @@
 
 #if defined(__EMSCRIPTEN__)
 
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
+
 void
 _Py_CheckEmscriptenSignals(void);
 
diff --git a/Include/internal/pycore_fileutils.h b/Include/internal/pycore_fileutils.h
index 0ed139f..25b383b 100644
--- a/Include/internal/pycore_fileutils.h
+++ b/Include/internal/pycore_fileutils.h
@@ -5,7 +5,7 @@ extern "C" {
 #endif
 
 #ifndef Py_BUILD_CORE
-#  error "Py_BUILD_CORE must be defined to include this header"
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 #include <locale.h>   /* struct lconv */
diff --git a/Include/internal/pycore_fileutils_windows.h b/Include/internal/pycore_fileutils_windows.h
index e804d38..b79aa9f 100644
--- a/Include/internal/pycore_fileutils_windows.h
+++ b/Include/internal/pycore_fileutils_windows.h
@@ -5,7 +5,7 @@ extern "C" {
 #endif
 
 #ifndef Py_BUILD_CORE
-#  error "Py_BUILD_CORE must be defined to include this header"
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 #ifdef MS_WINDOWS
diff --git a/Include/internal/pycore_frame.h b/Include/internal/pycore_frame.h
index 0dc2a18..ae77367 100644
--- a/Include/internal/pycore_frame.h
+++ b/Include/internal/pycore_frame.h
@@ -4,6 +4,10 @@
 extern "C" {
 #endif
 
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
+
 #include <stdbool.h>
 #include <stddef.h>               // offsetof()
 #include "pycore_code.h"          // STATS
diff --git a/Include/internal/pycore_import.h b/Include/internal/pycore_import.h
index 077508e..34f572b 100644
--- a/Include/internal/pycore_import.h
+++ b/Include/internal/pycore_import.h
@@ -5,6 +5,10 @@
 extern "C" {
 #endif
 
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
+
 #include "pycore_hashtable.h"     // _Py_hashtable_t
 #include "pycore_time.h"          // _PyTime_t
 
diff --git a/Include/internal/pycore_instruments.h b/Include/internal/pycore_instruments.h
index 56de9f8..e15447a 100644
--- a/Include/internal/pycore_instruments.h
+++ b/Include/internal/pycore_instruments.h
@@ -1,7 +1,9 @@
-
 #ifndef Py_INTERNAL_INSTRUMENT_H
 #define Py_INTERNAL_INSTRUMENT_H
 
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
 
 #include "pycore_bitutils.h"      // _Py_popcount32
 #include "pycore_frame.h"
diff --git a/Include/internal/pycore_intrinsics.h b/Include/internal/pycore_intrinsics.h
index 37d4efc..3a8dd95 100644
--- a/Include/internal/pycore_intrinsics.h
+++ b/Include/internal/pycore_intrinsics.h
@@ -1,3 +1,9 @@
+#ifndef Py_INTERNAL_INTRINSIC_H
+#define Py_INTERNAL_INTRINSIC_H
+
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
 
 /* Unary Functions: */
 #define INTRINSIC_1_INVALID                      0
@@ -40,3 +46,5 @@ typedef struct {
 
 extern const intrinsic_func1_info _PyIntrinsics_UnaryFunctions[];
 extern const intrinsic_func2_info _PyIntrinsics_BinaryFunctions[];
+
+#endif  // !Py_INTERNAL_INTRINSIC_H
diff --git a/Include/internal/pycore_opcode_metadata.h b/Include/internal/pycore_opcode_metadata.h
index 396d194..fab91e6 100644
--- a/Include/internal/pycore_opcode_metadata.h
+++ b/Include/internal/pycore_opcode_metadata.h
@@ -3,6 +3,10 @@
 //   Python/bytecodes.c
 // Do not edit!
 
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
+
 #include <stdbool.h>