libstdc++: Move some ranges algos to a new header <bits/ranges_algobase.h>

This roughly mirrors the existing split between <bits/stl_algo.h> and
<bits/stl_algobase.h>.  The ranges [specialized.algorithms] will use this new
header to avoid including all of of <bits/ranges_algo.h>.

libstdc++-v3/ChangeLog:

	* include/Makefile.am: Add bits/ranges_algobase.h
	* include/Makefile.in: Regenerate.
	* bits/ranges_algo.h: Include <bits/ranges_algobase.h> and refactor
	existing #includes.
	(__detail::__is_normal_iterator, __detail::is_reverse_iterator,
	__detail::__is_move_iterator, copy_result, move_result,
	__equal, equal, copy_result, move_result, move_backward_result,
	copy_backward_result, __copy_or_move_backward, __copy_or_move, copy,
	move, copy_backward, move_backward, copy_n_result, copy_n, fill_n,
	fill): Split out into ...
	* bits/range_algobase.h: ... this new header.

libstdc++-v3/ChangeLog

+2020-02-13  Patrick Palka  <ppalka@redhat.com>
+
+	* include/Makefile.am: Add bits/ranges_algobase.h
+	* include/Makefile.in: Regenerate.
+	* bits/ranges_algo.h: Include <bits/ranges_algobase.h> and refactor
+	existing #includes.
+	(__detail::__is_normal_iterator, __detail::is_reverse_iterator,
+	__detail::__is_move_iterator, copy_result, move_result,
+	__equal, equal, copy_result, move_result, move_backward_result,
+	copy_backward_result, __copy_or_move_backward, __copy_or_move, copy,
+	move, copy_backward, move_backward, copy_n_result, copy_n, fill_n,
+	fill): Split out into ...
+	* bits/range_algobase.h: ... this new header.
+
 2020-02-12  Patrick Palka  <ppalka@redhat.com>
 
 	LWG 3389 and LWG 3390

libstdc++-v3/include/Makefile.am

@@ -157,6 +157,7 @@ bits_headers = \
 	${bits_srcdir}/random.tcc \
 	${bits_srcdir}/range_access.h \
 	${bits_srcdir}/range_cmp.h \
+	${bits_srcdir}/ranges_algobase.h \
 	${bits_srcdir}/ranges_algo.h \
 	${bits_srcdir}/refwrap.h \
 	${bits_srcdir}/regex.h \

libstdc++-v3/include/Makefile.in

@@ -502,6 +502,7 @@ bits_headers = \
 	${bits_srcdir}/random.tcc \
 	${bits_srcdir}/range_access.h \
 	${bits_srcdir}/range_cmp.h \
+	${bits_srcdir}/ranges_algobase.h \
 	${bits_srcdir}/ranges_algo.h \
 	${bits_srcdir}/refwrap.h \
 	${bits_srcdir}/regex.h \