Don't convert sysconfig.get_config_var('VPATH') to an absolute path

this is required for venv to work properly

Makefile.pre.in

@@ -145,7 +145,6 @@ datarootdir=    @datarootdir@
 
 # Locations needed for semi-native fixup of sysconfig.
 srcdir_b2h=		@srcdir_b2h@
-VPATH_b2h=		@VPATH_b2h@
 abs_srcdir_b2h=		@abs_srcdir_b2h@
 abs_builddir_b2h=	@abs_builddir_b2h@
 prefix_b2h=		@prefix_b2h@

configure.ac

@@ -746,12 +746,8 @@ fi
 # without setting up the same env and also that the build of Python
 # itself will fail as the paths are not correct for the host tools.
 #
-# Also, getpath.c uses GetModuleFileNameW (replacing \ with /) and
-# compares that with the define VPATH (passed in via command-line)
-# to determine whether it's the build- or the installed-Python.
-#
 # To work around these issues a set of _b2h variables are created:
-# VPATH_b2h, prefix_b2h, srcdir_b2h, abs_srcdir_b2h
+# prefix_b2h, srcdir_b2h, abs_srcdir_b2h
 # and abs_builddir_b2h
 # .. where b2h stands for build to host. sysconfig.py replaces path
 # prefixes matching the non-b2h versions with the b2h equivalents.
@@ -778,10 +774,6 @@ AC_DEFUN([ABS_PATH_HOST],
 AC_SUBST([$1])
 ])
 
-AC_MSG_CHECKING(absolute host location of VPATH)
-ABS_PATH_HOST([VPATH_b2h],[srcdir])
-AC_MSG_RESULT([$VPATH_b2h])
-
 AC_MSG_CHECKING(absolute host location of prefix)
 ABS_PATH_HOST([prefix_b2h],[prefix])
 AC_MSG_RESULT([$prefix_b2h])