bpo-35081: Add pycore_ prefix to internal header files (GH-10263)

* Rename Include/internal/ header files:

  * pyatomic.h -> pycore_atomic.h
  * ceval.h -> pycore_ceval.h
  * condvar.h -> pycore_condvar.h
  * context.h -> pycore_context.h
  * pygetopt.h -> pycore_getopt.h
  * gil.h -> pycore_gil.h
  * hamt.h -> pycore_hamt.h
  * hash.h -> pycore_hash.h
  * mem.h -> pycore_mem.h
  * pystate.h -> pycore_state.h
  * warnings.h -> pycore_warnings.h

* PCbuild project, Makefile.pre.in, Modules/Setup: add the
  Include/internal/ directory to the search paths of header files.
* Update includes. For example, replace #include "internal/mem.h"
  with #include "pycore_mem.h".
diff --git a/Modules/Setup b/Modules/Setup
index fb16698..c180463 100644
--- a/Modules/Setup
+++ b/Modules/Setup
@@ -101,29 +101,29 @@
 # This only contains the minimal set of modules required to run the
 # setup.py script in the root of the Python source tree.
 
-posix -DPy_BUILD_CORE posixmodule.c	# posix (UNIX) system calls
+posix -DPy_BUILD_CORE -I$(srcdir)/Include/internal posixmodule.c # posix (UNIX) system calls
 errno errnomodule.c			# posix (UNIX) errno values
 pwd pwdmodule.c				# this is needed to find out the user's home dir
 					# if $HOME is not set
 _sre _sre.c				# Fredrik Lundh's new regular expressions
 _codecs _codecsmodule.c			# access to the builtin codecs and codec registry
 _weakref _weakref.c			# weak references
-_functools -DPy_BUILD_CORE _functoolsmodule.c   # Tools for working with functions and callable objects
+_functools -DPy_BUILD_CORE -I$(srcdir)/Include/internal _functoolsmodule.c   # Tools for working with functions and callable objects
 _operator _operator.c	        	# operator.add() and similar goodies
 _collections _collectionsmodule.c	# Container types
 _abc _abc.c				# Abstract base classes
 itertools itertoolsmodule.c		# Functions creating iterators for efficient looping
 atexit atexitmodule.c			# Register functions to be run at interpreter-shutdown
-_signal -DPy_BUILD_CORE signalmodule.c
+_signal -DPy_BUILD_CORE -I$(srcdir)/Include/internal signalmodule.c
 _stat _stat.c				# stat.h interface
-time -DPy_BUILD_CORE timemodule.c	# -lm # time operations and variables
-_thread -DPy_BUILD_CORE _threadmodule.c	# low-level threading interface
+time -DPy_BUILD_CORE -I$(srcdir)/Include/internal timemodule.c	# -lm # time operations and variables
+_thread -DPy_BUILD_CORE -I$(srcdir)/Include/internal _threadmodule.c	# low-level threading interface
 
 # access to ISO C locale support
 _locale _localemodule.c  # -lintl
 
 # Standard I/O baseline
-_io -DPy_BUILD_CORE -I$(srcdir)/Modules/_io _io/_iomodule.c _io/iobase.c _io/fileio.c _io/bytesio.c _io/bufferedio.c _io/textio.c _io/stringio.c
+_io -DPy_BUILD_CORE -I$(srcdir)/Include/internal -I$(srcdir)/Modules/_io _io/_iomodule.c _io/iobase.c _io/fileio.c _io/bytesio.c _io/bufferedio.c _io/textio.c _io/stringio.c
 
 # faulthandler module
 faulthandler faulthandler.c
diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index ff4172d..6c28b27 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -1,7 +1,7 @@
 
 #include "Python.h"
-#include "internal/mem.h"
-#include "internal/pystate.h"
+#include "pycore_mem.h"
+#include "pycore_state.h"
 #include "structmember.h"
 
 /* _functools module written and maintained
diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
index 2eb5262..24ae963 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -9,7 +9,7 @@
 
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
-#include "internal/pystate.h"
+#include "pycore_state.h"
 #include "structmember.h"
 #include "pythread.h"
 #include "_iomodule.h"
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index d33fa99..ad65188 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -3,7 +3,7 @@
 /* Interface to Sjoerd's portable C thread library */
 
 #include "Python.h"
-#include "internal/pystate.h"
+#include "pycore_state.h"
 #include "structmember.h" /* offsetof */
 #include "pythread.h"
 
diff --git a/Modules/_xxsubinterpretersmodule.c b/Modules/_xxsubinterpretersmodule.c
index 2eb8787..fb0b83a 100644
--- a/Modules/_xxsubinterpretersmodule.c
+++ b/Modules/_xxsubinterpretersmodule.c
@@ -4,7 +4,7 @@
 
 #include "Python.h"
 #include "frameobject.h"
-#include "internal/pystate.h"
+#include "pycore_state.h"
 
 
 static char *
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
index 4773c79..a54be07 100644
--- a/Modules/gcmodule.c
+++ b/Modules/gcmodule.c
@@ -24,9 +24,9 @@
 */
 
 #include "Python.h"
-#include "internal/context.h"
-#include "internal/mem.h"
-#include "internal/pystate.h"
+#include "pycore_context.h"
+#include "pycore_mem.h"
+#include "pycore_state.h"
 #include "frameobject.h"        /* for PyFrame_ClearFreeList */
 #include "pydtrace.h"
 #include "pytime.h"             /* for _PyTime_GetMonotonicClock() */
diff --git a/Modules/getpath.c b/Modules/getpath.c
index 521bc6e..53e5c2b 100644
--- a/Modules/getpath.c
+++ b/Modules/getpath.c
@@ -1,7 +1,7 @@
 /* Return the initial module search path. */
 
 #include "Python.h"
-#include "internal/pystate.h"
+#include "pycore_state.h"
 #include "osdefs.h"
 
 #include <sys/types.h>
diff --git a/Modules/main.c b/Modules/main.c
index 6a8aa05..1918f4f 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -2,9 +2,9 @@
 
 #include "Python.h"
 #include "osdefs.h"
-#include "internal/mem.h"
-#include "internal/pygetopt.h"
-#include "internal/pystate.h"
+#include "pycore_mem.h"
+#include "pycore_getopt.h"
+#include "pycore_state.h"
 
 #include <locale.h>
 
diff --git a/Modules/makesetup b/Modules/makesetup
index c7b0a60..bf5ca39 100755
--- a/Modules/makesetup
+++ b/Modules/makesetup
@@ -110,7 +110,7 @@
 	rulesf="@rules.$$"
 	trap 'rm -f $rulesf' 0 1 2 3
 	echo "
-# Rules appended by makedepend
+# Rules appended by makesetup
 " >$rulesf
 	DEFS=
 	BUILT=
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 9ccdc8e..0307436 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -32,7 +32,7 @@
 #else
 #include "winreparse.h"
 #endif
-#include "internal/pystate.h"
+#include "pycore_state.h"
 
 /* On android API level 21, 'AT_EACCESS' is not declared although
  * HAVE_FACCESSAT is defined. */
diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
index a81de6a..1915fd9 100644
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -4,7 +4,7 @@
 /* XXX Signals should be recorded per thread, now we have thread state. */
 
 #include "Python.h"
-#include "internal/pyatomic.h"
+#include "pycore_atomic.h"
 
 #ifndef MS_WINDOWS
 #include "posixmodule.h"