Completely revamp configure so that it preserves the standard make

variables CPPFLAGS, CFLAGS, CXXFLAGS, LDFLAGS and LIBS by moving
the configure additions to EXTRA_* variables.  Also, allow the user
to specify NOTEST_* values for all of the above, which eliminates the
need for THREAD_CPPFLAGS, THREAD_CFLAGS, and OPTIM.  Fix the setting
of INCLUDES and EXTRA_INCLUDES.  Check flags as they are added to
avoid pointless duplications.  Fix the order in which flags are given
on the compile and link lines.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@88960 13f79535-47bb-0310-9956-ffa450edef68