If a specific version of Python is present in the system, but the header file has not be found in {$prefix,/usr}/include/python$PYTHON_VERSION/, then the following loud warning message is issued:
If a specific version of Python is present in the system, but the header
file has not be found in {$prefix,/usr}/include/python$PYTHON_VERSION/, then
the following loud warning message is issued:

configure: WARNING: Header file for Python version 2.3 has not been found.
configure: WARNING: This probably means that an appropriate Python
configure: WARNING: development package needs to be installed.

(Aside note: we should replace in configure.ac and sysloc.in all the
instances of AC_MSG_RESULT by AC_MSG_WARN, when warning messages are
issued.)

svn path=/trunk/; revision=4834

FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot