Add ability to set libpython library
This relates to Bug 1995

diff --git a/configure.py b/configure.py
index 47b05c9..a11bdce 100644
--- a/configure.py
+++ b/configure.py
@@ -102,13 +102,14 @@
         def_qt_dir = "none"
 
     sys.stdout.write("Usage:\n")
-    sys.stdout.write("    python configure.py [-h] [-a tag] [-b dir] [-c] [-d dir] [-f] [-g dir] [-i] [-j #] [-k] [-l dir] [-m dir] [-n dir] [-o dir] [-q dir] [-r] [-s] [-u] [-v dir] [-w] [-y lib] option=value option+=value ...\n")
+    sys.stdout.write("    python configure.py [-h] [-a tag] [-b dir] [-c] [-d dir] [-e lib] [-f] [-g dir] [-i] [-j #] [-k] [-l dir] [-m dir] [-n dir] [-o dir] [-q dir] [-r] [-s] [-u] [-v dir] [-w] [-y lib] option=value option+=value ...\n")
     sys.stdout.write("where:\n")
     sys.stdout.write("  -h      display this help message\n")
     sys.stdout.write("  -a tag  explicitly enable the qtpe module\n")
     sys.stdout.write("  -b dir  where pyuic and pylupdate will be installed [default %s]\n" % opt_pyqtbindir)
     sys.stdout.write("  -c      concatenate each module's C/C++ source files\n")
     sys.stdout.write("  -d dir  where the PyTQt modules will be installed [default %\ns]" % opt_pyqtmoddir)
+    sys.stdout.write("  -y lib  explicitly specify the python library\n")
     sys.stdout.write("  -f      keep any existing features file (when cross-compiling) [default remove]\n")
     sys.stdout.write("  -g dir  where the TQt qconfig.h file can be found [default TQt include directory]\n")
     sys.stdout.write("  -i      enable checking of signed interpreters using the VendorID package [default disabled]\n")
@@ -1330,7 +1331,7 @@
 
     # Parse the command line.
     try:
-        optlist, args = getopt.getopt(argv[1:], "ha:b:cd:fg:ij:kl:m:n:o:q:rsuv:wy:")
+        optlist, args = getopt.getopt(argv[1:], "ha:b:cd:e:fg:ij:kl:m:n:o:q:rsuv:wy:")
     except getopt.GetoptError:
         usage()
 
@@ -1340,6 +1341,7 @@
     global opt_split, opt_tracing, opt_verbose, opt_keepfeatures
     global opt_qsciincdir, opt_qscilibdir, qsci_define
     global opt_vendorcheck, opt_vendincdir, opt_vendlibdir
+    global opt_libpython
 
     for opt, arg in optlist:
         if opt == "-h":
@@ -1352,6 +1354,8 @@
             opt_concat = 1
         elif opt == "-d":
             opt_pyqtmoddir = os.path.abspath(arg)
+        elif opt == "-e":
+            opt_libpython = arg
         elif opt == "-f":
             opt_keepfeatures = 1
         elif opt == "-g":
@@ -1437,6 +1441,9 @@
     if qtmod_lib:
         extra_libs.append(qtmod_lib)
 
+    if opt_libpython:
+        extra_libs.append(opt_libpython)
+
     if opt_vendorcheck:
         extra_include_dirs.append(opt_vendincdir)
         extra_lib_dir = opt_vendlibdir