./configure needs to properly enforce java version dependency

Added a javac version check >= 1.8 to configure.

refs #234

autoconf/configure.ac

@@ -160,7 +160,15 @@ AC_PATH_PROG(SWIG, swig, noswig, "/bin:/usr/bin:/usr/local/bin:/sw/bin")
 AS_IF([test "$ac_cv_path_SWIG" = "noswig"],AC_MSG_ERROR([could not find swig]),[])
 AC_PATH_PROG(GNUPLOT, gnuplot, nognuplot)
 AS_IF([test "$ac_cv_path_GNUPLOT" = "nognuplot"],AC_MSG_NOTICE([could not find gnuplot]),[])
+dnl AX_COMPARE_VERSION requires awk.
+AC_PROG_AWK
 AX_PROG_JAVA_CC(javac)
+JAVA_VER=`$JAVA_CC -version |& $ac_cv_path_PERL -ne 'print $& if /\d+\.\d+/'`
+AC_MSG_CHECKING([$JAVA_CC version >= 1.8])
+AX_COMPARE_VERSION([$JAVA_VER],[ge],[1.8], [AC_MSG_RESULT([yes])],
+ [AC_MSG_RESULT([no])
+  AC_MSG_ERROR([Trick requires javac version >= 1.8])
+ ])
 
 dnl look for libraries and headers we need to compile
 AC_PATH_X

configure

@@ -633,10 +633,10 @@ UDUNITS_HOME
 CLANG
 LLVM_CONFIG
 LLVM_HOME
-PYTHON_EXTRA_LDFLAGS
 PYTHON_EXTRA_LIBS
+PYTHON_EXTRA_LDFLAGS
 PYTHON_SITE_PKG
-PYTHON_LDFLAGS
+PYTHON_LIBS
 PYTHON_CPPFLAGS
 PYTHON_VERSION
 PTHREAD_CFLAGS
@@ -662,6 +662,7 @@ GCJ_OPTS
 ac_ct_JAVA_CC
 JAVA_CC_FLAGS
 JAVA_CC
+AWK
 GNUPLOT
 SWIG
 PYTHON
@@ -3688,6 +3689,48 @@ if test "$ac_cv_path_GNUPLOT" = "nognuplot"; then :
   { $as_echo "$as_me:${as_lineno-$LINENO}: could not find gnuplot" >&5
 $as_echo "$as_me: could not find gnuplot" >&6;}
 fi
+for ac_prog in gawk mawk nawk awk
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_AWK+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$AWK"; then
+  ac_cv_prog_AWK="$AWK" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_AWK="$ac_prog"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+AWK=$ac_cv_prog_AWK
+if test -n "$AWK"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $AWK" >&5
+$as_echo "$AWK" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+  test -n "$AWK" && break
+done
+
 if test -n "$ac_tool_prefix"; then
   for ac_prog in javac
   do
@@ -3799,6 +3842,49 @@ if test "$JAVA_CC" = "gcj"; then
 fi
 test -z "$JAVA_CC" && as_fn_error $? "no acceptable java compiler found in \$PATH" "$LINENO" 5
 
+JAVA_VER=`$JAVA_CC -version |& $ac_cv_path_PERL -ne 'print $& if /\d+\.\d+/'`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking $JAVA_CC version >= 1.8" >&5
+$as_echo_n "checking $JAVA_CC version >= 1.8... " >&6; }
+
+
+
+  # Used to indicate true or false condition
+  ax_compare_version=false
+
+  # Convert the two version strings to be compared into a format that
+  # allows a simple string comparison.  The end result is that a version
+  # string of the form 1.12.5-r617 will be converted to the form
+  # 0001001200050617.  In other words, each number is zero padded to four
+  # digits, and non digits are removed.
+
+  ax_compare_version_A=`echo "$JAVA_VER" | sed -e 's/\([0-9]*\)/Z\1Z/g' \
+                     -e 's/Z\([0-9]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([0-9][0-9]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([0-9][0-9][0-9]\)Z/Z0\1Z/g' \
+                     -e 's/[^0-9]//g'`
+
+
+  ax_compare_version_B=`echo "1.8" | sed -e 's/\([0-9]*\)/Z\1Z/g' \
+                     -e 's/Z\([0-9]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([0-9][0-9]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([0-9][0-9][0-9]\)Z/Z0\1Z/g' \
+                     -e 's/[^0-9]//g'`
+
+
+    ax_compare_version=`echo "x$ax_compare_version_A
+x$ax_compare_version_B" | sed 's/^ *//' | sort -r | sed "s/x${ax_compare_version_A}/true/;s/x${ax_compare_version_B}/false/;1q"`
+
+
+
+    if test "$ax_compare_version" = "true" ; then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+    else { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+  as_fn_error $? "Trick requires javac version >= 1.8" "$LINENO" 5
+
+  fi
+
 
 ac_ext=cpp
 ac_cpp='$CXXCPP $CPPFLAGS'
@@ -5100,7 +5186,7 @@ as_fn_error $? "
 This version of the AC_PYTHON_DEVEL macro
 doesn't work properly with versions of Python before
 2.1.0. You may need to re-run configure, setting the
-variables PYTHON_CPPFLAGS, PYTHON_LDFLAGS, PYTHON_SITE_PKG,
+variables PYTHON_CPPFLAGS, PYTHON_LIBS, PYTHON_SITE_PKG,
 PYTHON_EXTRA_LIBS and PYTHON_EXTRA_LDFLAGS by hand.
 Moreover, to disable this check, set PYTHON_NOVERSIONCHECK
 to something else than an empty string.
@@ -5185,7 +5271,7 @@ $as_echo "$PYTHON_CPPFLAGS" >&6; }
 	#
 	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for Python library path" >&5
 $as_echo_n "checking for Python library path... " >&6; }
-	if test -z "$PYTHON_LDFLAGS"; then
+	if test -z "$PYTHON_LIBS"; then
 		# (makes two attempts to ensure we've got a version number
 		# from the interpreter)
 		ac_python_version=`cat<<EOD | $PYTHON -
@@ -5243,25 +5329,25 @@ EOD`
 		then
 			# use the official shared library
 			ac_python_library=`echo "$ac_python_library" | sed "s/^lib//"`
-			PYTHON_LDFLAGS="-L$ac_python_libdir -l$ac_python_library"
+			PYTHON_LIBS="-L$ac_python_libdir -l$ac_python_library"
 		else
 			# old way: use libpython from python_configdir
 			ac_python_libdir=`$PYTHON -c \
 			  "from distutils.sysconfig import get_python_lib as f; \
 			  import os; \
 			  print (os.path.join(f(plat_specific=1, standard_lib=1), 'config'));"`
-			PYTHON_LDFLAGS="-L$ac_python_libdir -lpython$ac_python_version"
+			PYTHON_LIBS="-L$ac_python_libdir -lpython$ac_python_version"
 		fi
 
-		if test -z "PYTHON_LDFLAGS"; then
+		if test -z "PYTHON_LIBS"; then
 			as_fn_error $? "
   Cannot determine location of your Python DSO. Please check it was installed with
-  dynamic libraries enabled, or try setting PYTHON_LDFLAGS by hand.
+  dynamic libraries enabled, or try setting PYTHON_LIBS by hand.
 			" "$LINENO" 5
 		fi
 	fi
-	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $PYTHON_LDFLAGS" >&5
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $PYTHON_LIBS" >&5
-$as_echo "$PYTHON_LDFLAGS" >&6; }
+$as_echo "$PYTHON_LIBS" >&6; }
 
 
 	#
@@ -5282,13 +5368,13 @@ $as_echo "$PYTHON_SITE_PKG" >&6; }
 	#
 	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking python extra libraries" >&5
 $as_echo_n "checking python extra libraries... " >&6; }
-	if test -z "$PYTHON_EXTRA_LIBS"; then
+	if test -z "$PYTHON_EXTRA_LDFLAGS"; then
-	   PYTHON_EXTRA_LIBS=`$PYTHON -c "import distutils.sysconfig; \
+	   PYTHON_EXTRA_LDFLAGS=`$PYTHON -c "import distutils.sysconfig; \
                 conf = distutils.sysconfig.get_config_var; \
                 print (conf('LIBS') + ' ' + conf('SYSLIBS'))"`
 	fi
-	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $PYTHON_EXTRA_LIBS" >&5
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $PYTHON_EXTRA_LDFLAGS" >&5
-$as_echo "$PYTHON_EXTRA_LIBS" >&6; }
+$as_echo "$PYTHON_EXTRA_LDFLAGS" >&6; }
 
 
 	#
@@ -5296,13 +5382,13 @@ $as_echo "$PYTHON_EXTRA_LIBS" >&6; }
 	#
 	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking python extra linking flags" >&5
 $as_echo_n "checking python extra linking flags... " >&6; }
-	if test -z "$PYTHON_EXTRA_LDFLAGS"; then
+	if test -z "$PYTHON_EXTRA_LIBS"; then
-		PYTHON_EXTRA_LDFLAGS=`$PYTHON -c "import distutils.sysconfig; \
+		PYTHON_EXTRA_LIBS=`$PYTHON -c "import distutils.sysconfig; \
 			conf = distutils.sysconfig.get_config_var; \
 			print (conf('LINKFORSHARED'))"`
 	fi
-	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $PYTHON_EXTRA_LDFLAGS" >&5
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $PYTHON_EXTRA_LIBS" >&5
-$as_echo "$PYTHON_EXTRA_LDFLAGS" >&6; }
+$as_echo "$PYTHON_EXTRA_LIBS" >&6; }
 
 
 	#
@@ -5312,8 +5398,10 @@ $as_echo "$PYTHON_EXTRA_LDFLAGS" >&6; }
 $as_echo_n "checking consistency of all components of python development environment... " >&6; }
 	# save current global flags
 	ac_save_LIBS="$LIBS"
+	ac_save_LDFLAGS="$LDFLAGS"
 	ac_save_CPPFLAGS="$CPPFLAGS"
-	LIBS="$ac_save_LIBS $PYTHON_LDFLAGS $PYTHON_EXTRA_LDFLAGS $PYTHON_EXTRA_LIBS"
+	LIBS="$ac_save_LIBS $PYTHON_LIBS $PYTHON_EXTRA_LIBS $PYTHON_EXTRA_LIBS"
+	LDFLAGS="$ac_save_LDFLAGS $PYTHON_EXTRA_LDFLAGS"
 	CPPFLAGS="$ac_save_CPPFLAGS $PYTHON_CPPFLAGS"
 	ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'
@@ -5350,6 +5438,7 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
 	# turn back to default flags
 	CPPFLAGS="$ac_save_CPPFLAGS"
 	LIBS="$ac_save_LIBS"
+	LDFLAGS="$ac_save_LDFLAGS"
 
 	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $pythonexists" >&5
 $as_echo "$pythonexists" >&6; }
@@ -5360,8 +5449,8 @@ $as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
 as_fn_error $? "
   Could not link test program to Python. Maybe the main Python library has been
   installed in some non-standard library path. If so, pass it to configure,
-  via the LDFLAGS environment variable.
+  via the LIBS environment variable.
-  Example: ./configure LDFLAGS=\"-L/usr/non-standard-path/python/lib\"
+  Example: ./configure LIBS=\"-L/usr/non-standard-path/python/lib\"
   ============================================================================
    ERROR!
    You probably have to install the development version of the Python package
@@ -6628,6 +6717,7 @@ gives unlimited permission to copy, distribute and modify it."
 
 ac_pwd='$ac_pwd'
 srcdir='$srcdir'
+AWK='$AWK'
 test -n "\$AWK" || AWK=awk
 _ACEOF