* autogen.sh: export environment variable "PYTHON", for autoheader and autoconf

Patch by: Vincent Lefevre <vincent-svn {_AT_} vinc17.net>
          (Tweaked by me.)


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1903245 13f79535-47bb-0310-9956-ffa450edef68

Author: futatuki

autogen.sh

@@ -178,6 +178,7 @@ if test -z "$PYTHON"; then
   echo "to the Python executable, and re-run autogen.sh"
   exit 1
 fi
+export PYTHON
 
 # Compile SWIG headers into standalone C files if we are in release mode
 if test -n "$RELEASE_MODE"; then