lang/python{27,33,34}: Backport fix for upstream Issue #21166

Backport fix for upstream Issue #21166:

Prevent possible segfaults and other random failures of python
--generate-posix-vars in pybuilddir.txt build target by ensuring
that pybuilddir.txt is always regenerated when configure is run and
that the newly built skeleton python does not inadvertently import
modules from previously installed instances. [1]

This changeset has been committed for release in 2.7.9, 3.4.2, and 3.5.0.

A HUGE thank you to Ned Deily from the Python Core Development Team
for helping to identify the underlying cause, produce a fix and
wonderfully document the explanation.

[1] http://bugs.python.org/issue21166

1 files changed, 74 insertions, 0 deletions

diff --git a/lang/python34/files/patch-issue21166 b/lang/python34/files/patch-issue21166
new file mode 100644
index 000000000000..04bcd0406048
--- /dev/null
+++ b/lang/python34/files/patch-issue21166
@@ -0,0 +1,74 @@
+# HG changeset patch
+# User Ned Deily <nad@acm.org>
+# Date 1408739569 25200
+# Node ID e52d85f2e2846453dd0503613d28cf6967f113d7
+# Parent  d99014320220951707f79d114ae33f8c5a372a87
+Issue #21166: Prevent possible segfaults and other random failures of
+python --generate-posix-vars in pybuilddir.txt build target by ensuring
+that pybuilddir.txt is always regenerated when configure is run and
+that the newly built skeleton python does not inadvertently import
+modules from previously installed instances.
+
+diff --git a/Makefile.pre.in b/Makefile.pre.in
+--- Makefile.pre.in
++++ Makefile.pre.in
+@@ -546,8 +546,18 @@ platform: $(BUILDPYTHON) pybuilddir.txt
+ # Create build directory and generate the sysconfig build-time data there.
+ # pybuilddir.txt contains the name of the build dir and is used for
+ # sys.path fixup -- see Modules/getpath.c.
++# Since this step runs before shared modules are built, try to avoid bootstrap
++# problems by creating a dummy pybuildstr.txt just to allow interpreter
++# initialization to succeed.  It will be overwritten by generate-posix-vars
++# or removed in case of failure.
+ pybuilddir.txt: $(BUILDPYTHON)
+-	$(RUNSHARED) $(PYTHON_FOR_BUILD) -S -m sysconfig --generate-posix-vars
++	@echo "none" > ./pybuilddir.txt
++	$(RUNSHARED) $(PYTHON_FOR_BUILD) -S -m sysconfig --generate-posix-vars ;\
++	if test $$? -ne 0 ; then \
++		echo "generate-posix-vars failed" ; \
++		rm -f ./pybuilddir.txt ; \
++		exit 1 ; \
++	fi
+ 
+ # Build the shared modules
+ # Under GNU make, MAKEFLAGS are sorted and normalized; the 's' for
+diff --git a/Misc/NEWS b/Misc/NEWS
+--- Misc/NEWS
++++ Misc/NEWS
+@@ -242,6 +242,9 @@ Build
+ 
+ - Issue #21811: Anticipated fixes to support OS X versions > 10.9.
+ 
++- Issue #21166: Prevent possible segfaults and other random failures of
++  python --generate-posix-vars in pybuilddir.txt build target.
++
+ IDLE
+ ----
+ 
+diff --git a/configure b/configure
+--- configure
++++ configure
+@@ -2950,6 +2950,9 @@ case $host_os in *\ *) host_os=`echo "$h
+ 
+ 
+ 
++# pybuilddir.txt will be created by --generate-posix-vars in the Makefile
++rm -f pybuilddir.txt
++
+ if test "$cross_compiling" = yes; then
+     { $as_echo "$as_me:${as_lineno-$LINENO}: checking for python interpreter for cross build" >&5
+ $as_echo_n "checking for python interpreter for cross build... " >&6; }
+diff --git a/configure.ac b/configure.ac
+--- configure.ac
++++ configure.ac
+@@ -53,6 +53,9 @@ AC_CANONICAL_HOST
+ AC_SUBST(build)
+ AC_SUBST(host)
+ 
++# pybuilddir.txt will be created by --generate-posix-vars in the Makefile
++rm -f pybuilddir.txt
++
+ if test "$cross_compiling" = yes; then
+     AC_MSG_CHECKING([for python interpreter for cross build])
+     if test -z "$PYTHON_FOR_BUILD"; then
+