Issue #1584: Provide options to override default search paths for Tcl and Tk
when building _tkinter.  configure has two new options; if used, both must
be specified:

  ./configure \
      --with-tcltk-includes="-I/opt/local/include" \
      --with-tcltk-libs="-L/opt/local/lib -ltcl8.5 -ltk8.5"

In addition, the options can be overridden with make:

   make \
       TCLTK_INCLUDES="-I/opt/local/include" \
       TCLTK_LIBS="-L/opt/local/lib -ltcl8.6 -ltk8.6"
diff --git a/Makefile.pre.in b/Makefile.pre.in
index 84014b8..cf75650 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -196,6 +196,10 @@
 _PYTHON_HOST_PLATFORM=@_PYTHON_HOST_PLATFORM@
 HOST_GNU_TYPE=  @host@
 
+# Tcl and Tk config info from --with-tcltk-includes and -libs options
+TCLTK_INCLUDES=	@TCLTK_INCLUDES@
+TCLTK_LIBS=	@TCLTK_LIBS@
+
 # The task to run while instrument when building the profile-opt target
 PROFILE_TASK=	$(srcdir)/Tools/pybench/pybench.py -n 2 --with-gc --with-syscheck
 #PROFILE_TASK=	$(srcdir)/Lib/test/regrtest.py
@@ -456,6 +460,7 @@
 	    *) quiet="";; \
 	esac; \
 	$(RUNSHARED) CC='$(CC)' LDSHARED='$(BLDSHARED)' OPT='$(OPT)' \
+		_TCLTK_INCLUDES='$(TCLTK_INCLUDES)' _TCLTK_LIBS='$(TCLTK_LIBS)' \
 		$(PYTHON_FOR_BUILD) $(srcdir)/setup.py $$quiet build
 
 # Build static library
diff --git a/Misc/NEWS b/Misc/NEWS
index 5dc2870..a71a6a7 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -280,6 +280,9 @@
   OS X 10.8 systems because the Apple-deprecated QuickDraw headers have
   been removed from Xcode 4.  Skip building it in this case.
 
+- Issue #1584: Provide options to override default search paths for
+  Tcl and Tk when building _tkinter.
+
 IDLE
 ----
 
diff --git a/configure b/configure
index 68e4784..f865054 100755
--- a/configure
+++ b/configure
@@ -644,6 +644,8 @@
 USE_THREAD_MODULE
 SIGNAL_OBJS
 USE_SIGNAL_MODULE
+TCLTK_LIBS
+TCLTK_INCLUDES
 LIBFFI_INCLUDEDIR
 PKG_CONFIG
 SHLIBS
@@ -786,6 +788,8 @@
 with_libs
 with_system_expat
 with_system_ffi
+with_tcltk_includes
+with_tcltk_libs
 with_dbmliborder
 with_signal_module
 with_dec_threads
@@ -1459,6 +1463,10 @@
   --with-system-expat     build pyexpat module using an installed expat
                           library
   --with-system-ffi       build _ctypes module using an installed ffi library
+  --with-tcltk-includes='-I...'
+                          override search for Tcl and Tk include files
+  --with-tcltk-libs='-L...'
+                          override search for Tcl and Tk libs
   --with-dbmliborder=db1:db2:...
                           order to check db backends for dbm. Valid value is a
                           colon separated string with the backend names
@@ -8954,6 +8962,46 @@
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $with_system_ffi" >&5
 $as_echo "$with_system_ffi" >&6; }
 
+# Check for --with-tcltk-includes=path and --with-tcltk-libs=path
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for --with-tcltk-includes" >&5
+$as_echo_n "checking for --with-tcltk-includes... " >&6; }
+
+# Check whether --with-tcltk-includes was given.
+if test "${with_tcltk_includes+set}" = set; then :
+  withval=$with_tcltk_includes;
+else
+  with_tcltk_includes="default"
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $with_tcltk_includes" >&5
+$as_echo "$with_tcltk_includes" >&6; }
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for --with-tcltk-libs" >&5
+$as_echo_n "checking for --with-tcltk-libs... " >&6; }
+
+# Check whether --with-tcltk-libs was given.
+if test "${with_tcltk_libs+set}" = set; then :
+  withval=$with_tcltk_libs;
+else
+  with_tcltk_libs="default"
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $with_tcltk_libs" >&5
+$as_echo "$with_tcltk_libs" >&6; }
+if test "x$with_tcltk_includes" = xdefault || test "x$with_tcltk_libs" = xdefault
+then
+  if test "x$with_tcltk_includes" != "x$with_tcltk_libs"
+  then
+    as_fn_error $? "use both --with-tcltk-includes='...' and --with-tcltk-libs='...' or neither" "$LINENO" 5
+  fi
+  TCLTK_INCLUDES=""
+  TCLTK_LIBS=""
+else
+  TCLTK_INCLUDES="$with_tcltk_includes"
+  TCLTK_LIBS="$with_tcltk_libs"
+fi
+
 # Check for --with-dbmliborder
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for --with-dbmliborder" >&5
 $as_echo_n "checking for --with-dbmliborder... " >&6; }
diff --git a/configure.ac b/configure.ac
index d922bc7..891d568 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2289,6 +2289,34 @@
 
 AC_MSG_RESULT($with_system_ffi)
 
+# Check for --with-tcltk-includes=path and --with-tcltk-libs=path
+AC_SUBST(TCLTK_INCLUDES)
+AC_SUBST(TCLTK_LIBS)
+AC_MSG_CHECKING(for --with-tcltk-includes)
+AC_ARG_WITH(tcltk-includes,
+            AS_HELP_STRING([--with-tcltk-includes='-I...'], [override search for Tcl and Tk include files]),
+            [],
+            [with_tcltk_includes="default"])
+AC_MSG_RESULT($with_tcltk_includes)
+AC_MSG_CHECKING(for --with-tcltk-libs)
+AC_ARG_WITH(tcltk-libs,
+            AS_HELP_STRING([--with-tcltk-libs='-L...'], [override search for Tcl and Tk libs]),
+            [],
+            [with_tcltk_libs="default"])
+AC_MSG_RESULT($with_tcltk_libs)
+if test "x$with_tcltk_includes" = xdefault || test "x$with_tcltk_libs" = xdefault
+then
+  if test "x$with_tcltk_includes" != "x$with_tcltk_libs"
+  then
+    AC_MSG_ERROR([use both --with-tcltk-includes='...' and --with-tcltk-libs='...' or neither])
+  fi
+  TCLTK_INCLUDES=""
+  TCLTK_LIBS=""
+else
+  TCLTK_INCLUDES="$with_tcltk_includes"
+  TCLTK_LIBS="$with_tcltk_libs"
+fi
+
 # Check for --with-dbmliborder
 AC_MSG_CHECKING(for --with-dbmliborder)
 AC_ARG_WITH(dbmliborder,
diff --git a/setup.py b/setup.py
index de4392f..831fa2a 100644
--- a/setup.py
+++ b/setup.py
@@ -1729,6 +1729,41 @@
 
         return missing
 
+    def detect_tkinter_explicitly(self):
+        # Build _tkinter using explicit locations for Tcl/Tk.
+        #
+        # This is enabled when both arguments are given to ./configure:
+        #
+        #     --with-tcltk-includes="-I/path/to/tclincludes \
+        #                            -I/path/to/tkincludes"
+        #     --with-tcltk-libs="-L/path/to/tcllibs -ltclm.n \
+        #                        -L/path/to/tklibs -ltkm.n"
+        #
+        # These values can also be specified or overriden via make:
+        #    make TCLTK_INCLUDES="..." TCLTK_LIBS="..."
+        #
+        # This can be useful for building and testing tkinter with multiple
+        # versions of Tcl/Tk.  Note that a build of Tk depends on a particular
+        # build of Tcl so you need to specify both arguments and use care when
+        # overriding.
+
+        # The _TCLTK variables are created in the Makefile sharedmods target.
+        tcltk_includes = os.environ.get('_TCLTK_INCLUDES')
+        tcltk_libs = os.environ.get('_TCLTK_LIBS')
+        if not (tcltk_includes and tcltk_libs):
+            # Resume default configuration search.
+            return 0
+
+        extra_compile_args = tcltk_includes.split()
+        extra_link_args = tcltk_libs.split()
+        ext = Extension('_tkinter', ['_tkinter.c', 'tkappinit.c'],
+                        define_macros=[('WITH_APPINIT', 1)],
+                        extra_compile_args = extra_compile_args,
+                        extra_link_args = extra_link_args,
+                        )
+        self.extensions.append(ext)
+        return 1
+
     def detect_tkinter_darwin(self, inc_dirs, lib_dirs):
         # The _tkinter module, using frameworks. Since frameworks are quite
         # different the UNIX search logic is not sharable.
@@ -1811,10 +1846,16 @@
         self.extensions.append(ext)
         return 1
 
-
     def detect_tkinter(self, inc_dirs, lib_dirs):
         # The _tkinter module.
 
+        # Check whether --with-tcltk-includes and --with-tcltk-libs were
+        # configured or passed into the make target.  If so, use these values
+        # to build tkinter and bypass the searches for Tcl and TK in standard
+        # locations.
+        if self.detect_tkinter_explicitly():
+            return
+
         # Rather than complicate the code below, detecting and building
         # AquaTk is a separate method. Only one Tkinter will be built on
         # Darwin - either AquaTk, if it is found, or X11 based Tk.