Changes from Bernie Bright:

Added '--with-cxx=COMPILER[:flags]' to ./configure in order to set the
compiler and flags.  If this option is omitted then the default compiler
is assumed (ie the current behaviour).  This duplicates the effect of
passing CC, CFLAGS, CXX and CXXFLAGS on the command line to configure
and make.

SimGear/simgear/compiler.h
Initial support for KAI C++ on linux.

SimGear/simgear/ephemeris/celestialBody.[ch]xx
Removed extraneous semicolons.

SimGear/simgear/io/sg_file.cxx
MSVC tidy up.

acsite.m4

@@ -392,3 +392,24 @@ if test "$have_timezone" = no; then
          AC_MSG_RESULT(no))
 fi
 ])dnl
+
+## AC_BZ_SET_COMPILER: Addition by Theodore Papadopoulo
+## Patch by Jim McKelvey: change sed -e 's/ /@/g' to sed -e 's/ /@/'
+AC_DEFUN(AC_SG_SET_COMPILER,
+  [cxxwith=`echo $1 | sed -e 's/ /@/'`
+   case "$cxxwith" in
+     *:*@*)                 # Full initialization syntax
+       CXX=`echo "$cxxwith" | sed  -n -e 's/.*:\(.*\)@.*/\1/p'`
+       CXXFLAGS=`echo "$cxxwith" | sed  -n -e 's/.*:.*@\(.*\)/\1/p'`
+     ;;
+     *:*)                   # Simple initialization syntax
+       CXX=`echo "$cxxwith" | sed  -n -e 's/.*:\(.*\)/\1/p'`
+       CXXFLAGS=$3
+     ;;
+     *)                     # Default values
+       CXX=$2
+       CXXFLAGS=$3
+       CC="$2 --c"
+##       CFLAGS=
+     ;;
+   esac])