bpo-23404: make touch becomes make regen-all (#1466)

Don't rebuild generated files based on file modification time
anymore, the action is now explicit. Replace "make touch"
with "make regen-all".

Changes:

* Remove "make touch", Tools/hg/hgtouch.py and .hgtouch
* Add a new "make regen-all" command to rebuild all generated files
* Add subcommands to only generate specific files:

  - regen-ast: Include/Python-ast.h and Python/Python-ast.c
  - regen-grammar: Include/graminit.h and Python/graminit.c
  - regen-opcode-targets: Python/opcode_targets.h

* Add PYTHON_FOR_REGEN variable
* pgen is now only built by by "make regen-grammar"
* Add $(srcdir)/ prefix to paths to source files to handle correctly
  compilation outside the source directory

1 files changed, 47 insertions, 6 deletions

diff --git a/configure b/configure
index 8c91735124..6123e21109 100755
--- a/configure
+++ b/configure
@@ -740,8 +740,8 @@ UNIVERSALSDK
 CONFIG_ARGS
 SOVERSION
 VERSION
-GENERATED_COMMENT
 PYTHON_FOR_BUILD
+PYTHON_FOR_REGEN
 host_os
 host_vendor
 host_cpu
@@ -2902,6 +2902,51 @@ case $host_os in *\ *) host_os=`echo "$host_os" | sed 's/ /-/g'`;; esac
 # pybuilddir.txt will be created by --generate-posix-vars in the Makefile
 rm -f pybuilddir.txt
 
+for ac_prog in python$PACKAGE_VERSION python3 python
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_PYTHON_FOR_REGEN+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$PYTHON_FOR_REGEN"; then
+  ac_cv_prog_PYTHON_FOR_REGEN="$PYTHON_FOR_REGEN" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_PYTHON_FOR_REGEN="$ac_prog"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+PYTHON_FOR_REGEN=$ac_cv_prog_PYTHON_FOR_REGEN
+if test -n "$PYTHON_FOR_REGEN"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $PYTHON_FOR_REGEN" >&5
+$as_echo "$PYTHON_FOR_REGEN" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+  test -n "$PYTHON_FOR_REGEN" && break
+done
+test -n "$PYTHON_FOR_REGEN" || PYTHON_FOR_REGEN="python3"
+
+
+
 if test "$cross_compiling" = yes; then
     { $as_echo "$as_me:${as_lineno-$LINENO}: checking for python interpreter for cross build" >&5
 $as_echo_n "checking for python interpreter for cross build... " >&6; }
@@ -2918,20 +2963,16 @@ $as_echo_n "checking for python interpreter for cross build... " >&6; }
 	fi
         { $as_echo "$as_me:${as_lineno-$LINENO}: result: $interp" >&5
 $as_echo "$interp" >&6; }
-	PYTHON_FOR_BUILD='_PYTHON_PROJECT_BASE=$(abs_builddir) _PYTHON_HOST_PLATFORM=$(_PYTHON_HOST_PLATFORM) PYTHONPATH=$(shell test -f pybuilddir.txt && echo $(abs_builddir)/`cat pybuilddir.txt`:)$(srcdir)/Lib:$(srcdir)/Lib/$(PLATDIR) '$interp
+	PYTHON_FOR_BUILD='_PYTHON_PROJECT_BASE=$(abs_builddir) _PYTHON_HOST_PLATFORM=$(_PYTHON_HOST_PLATFORM) PYTHONPATH=$(shell test -f pybuilddir.txt && echo $(abs_builddir)/`cat pybuilddir.txt`:)$(srcdir)/Lib _PYTHON_SYSCONFIGDATA_NAME=_sysconfigdata_$(ABIFLAGS)_$(MACHDEP)_$(MULTIARCH) '$interp
     fi
-    # Used to comment out stuff for rebuilding generated files
-    GENERATED_COMMENT='#'
 elif test "$cross_compiling" = maybe; then
     as_fn_error $? "Cross compiling required --host=HOST-TUPLE and --build=ARCH" "$LINENO" 5
 else
     PYTHON_FOR_BUILD='./$(BUILDPYTHON) -E'
-    GENERATED_COMMENT=''
 fi
 
 
 
-
 if test "$prefix" != "/"; then
     prefix=`echo "$prefix" | sed -e 's/\/$//g'`
 fi