Reduce the number of times we build a host copy of python.

ports/python/nacl.patch

 diff --git a/Include/datetime.h b/Include/datetime.h
 index c0e7ffd..b6d6036 100644
 --- a/Include/datetime.h
 +++ b/Include/datetime.h
 @@ -166,6 +166,8 @@ typedef struct {
  
  #ifdef Py_BUILD_CORE
  
 +#define PyDataTime_STATIC 1
 +
@@ skipping 464 matching lines @@
      if test -z "$PYTHON_FOR_BUILD"; then
 -        for interp in python$PACKAGE_VERSION python2 python; do
 -           which $interp >/dev/null 2>&1 || continue
 -           if $interp -c 'import sys;sys.exit(not (sys.version_info[:2] >= (2,7) and sys.version_info[0] < 3))'; then
 -               break
 -           fi
 -            interp=
 -       done
 +       case "$host" in
 +       *-*-nacl*)
-+           interp=$(cd ../build-nacl-host && pwd)/python.exe
-+           if [ ! -f $interp ]; then interp=$(cd ../build-nacl-host && pwd)/python; fi
++           interp=$(cd ../../python-host/build_host && pwd)/python.exe
++           if [ ! -f $interp ]; then interp=$(cd ../../python-host/build_host && pwd)/python; fi
 +           ;;
 +       *)
 +           for interp in python$PACKAGE_VERSION python2 python; do
 +               which $interp >/dev/null 2>&1 || continue
 +               if $interp -c 'import sys;sys.exit(not (sys.version_info@<:@:2@:>@ >= (2,7) and sys.version_info@<:@0@:>@ < 3))'; then
 +                   break
 +               fi
 +               interp=
 +           done
 +           ;;
@@ skipping 84 matching lines @@
      if test -z "$PYTHON_FOR_BUILD"; then
 -        for interp in python$PACKAGE_VERSION python2 python; do
 -           which $interp >/dev/null 2>&1 || continue
 -           if $interp -c 'import sys;sys.exit(not (sys.version_info@<:@:2@:>@ >= (2,7) and sys.version_info@<:@0@:>@ < 3))'; then
 -               break
 -           fi
 -            interp=
 -       done
 +       case "$host" in
 +       *-*-nacl*)
-+           interp=$(cd ../build-nacl-host && pwd)/python
++           interp=$(cd ../../python-host/build_host && pwd)/python
 +           ;;
 +       *)
 +           for interp in python$PACKAGE_VERSION python2 python; do
 +               which $interp >/dev/null 2>&1 || continue
 +               if $interp -c 'import sys;sys.exit(not (sys.version_info@<:@:2@:>@ >= (2,7) and sys.version_info@<:@0@:>@ < 3))'; then
 +                   break
 +               fi
 +               interp=
 +           done
 +           ;;
@@ skipping 53 matching lines @@
         OpenUNIX*|UnixWare*)
 @@ -2121,7 +2140,7 @@ then
             LINKFORSHARED="-Wl,-E -Wl,+s";;
  #          LINKFORSHARED="-Wl,-E -Wl,+s -Wl,+b\$(BINLIBDEST)/lib-dynload";;
         BSD/OS/4*) LINKFORSHARED="-Xlinker -export-dynamic";;
 -       Linux*|GNU*) LINKFORSHARED="-Xlinker -export-dynamic";;
 +       Linux*|GNU*|NaCl*) LINKFORSHARED="-Xlinker -export-dynamic";;
         # -u libsys_s pulls in all symbols in libsys
         Darwin/*) 
                 # -u _PyMac_Error is needed to pull in the mac toolbox glue,