Limit the set of strings.h functions also exposed in string.h.

As someone who can remember when you might not be able to include both
string.h and strings.h at the same time, it annoys me that strings.h
still exists and is the only standard source for str(n)casecmp(_l) and
ffs.  I think it’s right that we expose those functions from string.h.
However, there’s no reason we need to keep exposing the other obsolete
functions that strings.h declares from string.h.

This patch creates <bits/strings_x2k8.h>, which declares the
non-obsolete functions whose official home is strings.h.  strings.h
includes it unconditionally, and string.h includes it under
__USE_MISC, instead of strings.h.

Two tests of the obsolete strings.h functions had to be adjusted.

	* string/strings.h (strcasecmp, strncasecmp, strcasecmp_l)
	(strncasecmp_l, ffs, ffsl, ffsll): Move declarations to...
	* string/bits/strings_x2k8.h: ... this new file.
	* string/Makefile: Install bits/strings_x2k8.h.
	* include/bits/strings_x2k8h: New wrapper.
	* string/string.h: Include bits/strings_x2k8.h instead of
	strings.h.

	* debug/tst-chk1.c, string/test-string.h: Include strings.h.
	* scripts/check-obsolete-constructs.py: string.h is no longer
	expected to include strings.h.

	* sysdeps/i386/i686/multiarch/bcopy.c
	* sysdeps/i386/i686/multiarch/bzero.c
	* sysdeps/i386/i686/multiarch/ifunc-impl-list.c
	* sysdeps/powerpc/powerpc32/power4/multiarch/ifunc-impl-list.c
	* sysdeps/powerpc/powerpc64/multiarch/bcopy-ppc64.c
	* sysdeps/powerpc/powerpc64/multiarch/bcopy.c
	* sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
	* sysdeps/s390/bzero.c
	* sysdeps/s390/multiarch/ifunc-impl-list.c
	* sysdeps/sparc/sparc64/multiarch/bzero.c
	* sysdeps/sparc/sparc64/multiarch/ifunc-impl-list.c:
        Include strings.h.

20 files changed, 91 insertions, 40 deletions

diff --git a/NEWS b/NEWS
index 599db8f..93be478 100644
--- a/NEWS
+++ b/NEWS
@@ -187,6 +187,9 @@ Deprecated and removed features, and other changes affecting compatibility:
 * The obsolete and never-implemented XSI STREAMS header files <stropts.h>
   and <sys/stropts.h> have been removed.
 
+* The obsolete functions bcmp, bcopy, bzero, index, and rindex are no
+  longer declared in <string.h>, only <strings.h>.
+
 * The typedefs u_int8_t, u_int16_t, u_int32_t, u_int64_t, and register_t
   are no longer defined by <sys/types.h> in strict conformance modes.
   These types were historically provided by <sys/types.h> on BSD systems,
diff --git a/debug/tst-chk1.c b/debug/tst-chk1.c
index 5d02592..ae7d0c2 100644
--- a/debug/tst-chk1.c
+++ b/debug/tst-chk1.c
@@ -30,6 +30,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h>
 #include <unistd.h>
 #include <wchar.h>
 #include <sys/poll.h>
diff --git a/include/bits/strings_x2k8.h b/include/bits/strings_x2k8.h
new file mode 100644
index 0000000..7eddd92
--- /dev/null
+++ b/include/bits/strings_x2k8.h
@@ -0,0 +1 @@
+#include <string/bits/strings_x2k8.h>
diff --git a/scripts/check-obsolete-constructs.py b/scripts/check-obsolete-constructs.py
index 77253df..dfe0d0f 100755
--- a/scripts/check-obsolete-constructs.py
+++ b/scripts/check-obsolete-constructs.py
@@ -506,7 +506,6 @@ HEADER_ALLOWED_INCLUDES = {
     "inttypes.h":                  [ "stdint.h" ],
     "signal.h":                    [ "sys/ucontext.h" ],
     "stdlib.h":                    [ "alloca.h", "sys/types.h" ],
-    "string.h":                    [ "strings.h" ],
     "tgmath.h":                    [ "complex.h", "math.h" ],
     "threads.h":                   [ "time.h" ],
 
diff --git a/string/Makefile b/string/Makefile
index c46785f..d9503bd 100644
--- a/string/Makefile
+++ b/string/Makefile
@@ -23,7 +23,7 @@ subdir	:= string
 include ../Makeconfig
 
 headers		:= string.h bits/string_fortified.h			\
-		   strings.h bits/strings_fortified.h			\
+		   strings.h bits/strings_x2k8.h bits/strings_fortified.h \
 		   byteswap.h bits/byteswap.h				\
 		   endian.h bits/endian.h bits/endianness.h		\
 		   bits/uintn-identity.h				\
diff --git a/string/bits/strings_x2k8.h b/string/bits/strings_x2k8.h
new file mode 100644
index 0000000..dbcb0b2
--- /dev/null
+++ b/string/bits/strings_x2k8.h
@@ -0,0 +1,70 @@
+/* Copyright (C) 2019 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_STRINGS_X2K8_H
+#define _BITS_STRINGS_X2K8_H 1
+
+/* This header file declares all of the strings.h functions that are
+   not marked as "obsolete" in POSIX.1-2008.  As a GNU extension,
+   these functions are also made available via string.h.  */
+
+#if !defined _STRING_H && !defined _STRINGS_H
+# error "Never include <bits/strings_x2k8.h> directly, use <string(s).h>."
+#endif
+
+__BEGIN_DECLS
+
+/* Compare S1 and S2, ignoring case.  */
+extern int strcasecmp (const char *__s1, const char *__s2)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+
+/* Compare no more than N chars of S1 and S2, ignoring case.  */
+extern int strncasecmp (const char *__s1, const char *__s2, size_t __n)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+
+#ifdef	__USE_XOPEN2K8
+/* POSIX.1-2008 extended locale interface (see locale.h).  */
+# include <bits/types/locale_t.h>
+
+/* Compare S1 and S2, ignoring case, using collation rules from LOC.  */
+extern int strcasecmp_l (const char *__s1, const char *__s2, locale_t __loc)
+     __THROW __attribute_pure__ __nonnull ((1, 2, 3));
+
+/* Compare no more than N chars of S1 and S2, ignoring case, using
+   collation rules from LOC.  */
+extern int strncasecmp_l (const char *__s1, const char *__s2,
+			  size_t __n, locale_t __loc)
+     __THROW __attribute_pure__ __nonnull ((1, 2, 4));
+#endif
+
+#if defined __USE_MISC || !defined __USE_XOPEN2K8 || defined __USE_XOPEN2K8XSI
+/* Return the position of the first bit set in I, or 0 if none are set.
+   The least-significant bit is position 1, the most-significant 32.  */
+extern int ffs (int __i) __THROW __attribute_const__;
+#endif
+
+/* The following two functions are non-standard but necessary for non-32 bit
+   platforms.  */
+#ifdef	__USE_MISC
+extern int ffsl (long int __l) __THROW __attribute_const__;
+__extension__ extern int ffsll (long long int __ll)
+     __THROW __attribute_const__;
+#endif
+
+__END_DECLS
+
+#endif /* bits/strings_x2k8.h */
diff --git a/string/string.h b/string/string.h
index 234ee91..fcb7da8 100644
--- a/string/string.h
+++ b/string/string.h
@@ -427,7 +427,7 @@ extern char *strerror_l (int __errnum, locale_t __l) __THROW;
 #endif
 
 #ifdef __USE_MISC
-# include <strings.h>
+# include <bits/strings_x2k8.h>
 
 /* Set N bytes of S to 0.  The compiler will not delete a call to this
    function, even if S is dead after the call.  */
diff --git a/string/strings.h b/string/strings.h
index 65dfca8..540eb15 100644
--- a/string/strings.h
+++ b/string/strings.h
@@ -21,6 +21,8 @@
 #include <features.h>
 #include <bits/types/size_t.h>
 
+#include <bits/strings_x2k8.h>
+
 /* Tell the caller that we provide correct C++ prototypes.  */
 #if defined __cplusplus && __GNUC_PREREQ (4, 4)
 # define __CORRECT_ISO_CPP_STRINGS_H_PROTO
@@ -97,43 +99,6 @@ extern char *rindex (const char *__s, int __c)
 # endif
 #endif
 
-#if defined __USE_MISC || !defined __USE_XOPEN2K8 || defined __USE_XOPEN2K8XSI
-/* Return the position of the first bit set in I, or 0 if none are set.
-   The least-significant bit is position 1, the most-significant 32.  */
-extern int ffs (int __i) __THROW __attribute_const__;
-#endif
-
-/* The following two functions are non-standard but necessary for non-32 bit
-   platforms.  */
-# ifdef	__USE_MISC
-extern int ffsl (long int __l) __THROW __attribute_const__;
-__extension__ extern int ffsll (long long int __ll)
-     __THROW __attribute_const__;
-# endif
-
-/* Compare S1 and S2, ignoring case.  */
-extern int strcasecmp (const char *__s1, const char *__s2)
-     __THROW __attribute_pure__ __nonnull ((1, 2));
-
-/* Compare no more than N chars of S1 and S2, ignoring case.  */
-extern int strncasecmp (const char *__s1, const char *__s2, size_t __n)
-     __THROW __attribute_pure__ __nonnull ((1, 2));
-
-#ifdef	__USE_XOPEN2K8
-/* POSIX.1-2008 extended locale interface (see locale.h).  */
-# include <bits/types/locale_t.h>
-
-/* Compare S1 and S2, ignoring case, using collation rules from LOC.  */
-extern int strcasecmp_l (const char *__s1, const char *__s2, locale_t __loc)
-     __THROW __attribute_pure__ __nonnull ((1, 2, 3));
-
-/* Compare no more than N chars of S1 and S2, ignoring case, using
-   collation rules from LOC.  */
-extern int strncasecmp_l (const char *__s1, const char *__s2,
-			  size_t __n, locale_t __loc)
-     __THROW __attribute_pure__ __nonnull ((1, 2, 4));
-#endif
-
 __END_DECLS
 
 #if __GNUC_PREREQ (3,4) && __USE_FORTIFY_LEVEL > 0 \
diff --git a/string/test-string.h b/string/test-string.h
index 0efe5d8..a6d8d1e 100644
--- a/string/test-string.h
+++ b/string/test-string.h
@@ -55,6 +55,7 @@ extern impl_t __start_impls[], __stop_impls[];
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h>
 #include <sys/mman.h>
 #include <sys/param.h>
 #include <unistd.h>
diff --git a/sysdeps/i386/i686/multiarch/bcopy.c b/sysdeps/i386/i686/multiarch/bcopy.c
index 2145ab7..929dc70 100644
--- a/sysdeps/i386/i686/multiarch/bcopy.c
+++ b/sysdeps/i386/i686/multiarch/bcopy.c
@@ -21,6 +21,7 @@
 #if IS_IN (libc)
 # define bcopy __redirect_bcopy
 # include <string.h>
+# include <strings.h>
 # undef bcopy
 
 # define SYMBOL_NAME bcopy
diff --git a/sysdeps/i386/i686/multiarch/bzero.c b/sysdeps/i386/i686/multiarch/bzero.c
index 3b68e1c..3655262 100644
--- a/sysdeps/i386/i686/multiarch/bzero.c
+++ b/sysdeps/i386/i686/multiarch/bzero.c
@@ -21,6 +21,7 @@
 #if IS_IN (libc)
 # define bzero __redirect_bzero
 # include <string.h>
+# include <strings.h>
 # undef bzero
 
 # define SYMBOL_NAME bzero
diff --git a/sysdeps/i386/i686/multiarch/ifunc-impl-list.c b/sysdeps/i386/i686/multiarch/ifunc-impl-list.c
index 23774fb..8101c0a 100644
--- a/sysdeps/i386/i686/multiarch/ifunc-impl-list.c
+++ b/sysdeps/i386/i686/multiarch/ifunc-impl-list.c
@@ -18,6 +18,7 @@
 
 #include <assert.h>
 #include <string.h>
+#include <strings.h>
 #include <wchar.h>
 #include <ifunc-impl-list.h>
 #include "init-arch.h"
diff --git a/sysdeps/powerpc/powerpc32/power4/multiarch/ifunc-impl-list.c b/sysdeps/powerpc/powerpc32/power4/multiarch/ifunc-impl-list.c
index fca6c2c..07de0a9 100644
--- a/sysdeps/powerpc/powerpc32/power4/multiarch/ifunc-impl-list.c
+++ b/sysdeps/powerpc/powerpc32/power4/multiarch/ifunc-impl-list.c
@@ -18,6 +18,7 @@
 
 #include <assert.h>
 #include <string.h>
+#include <strings.h>
 #include <wchar.h>
 #include <ldsodefs.h>
 #include <ifunc-impl-list.h>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/bcopy-ppc64.c b/sysdeps/powerpc/powerpc64/multiarch/bcopy-ppc64.c
index 0851afa..4b530cd 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/bcopy-ppc64.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/bcopy-ppc64.c
@@ -17,6 +17,7 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <string.h>
+#include <strings.h>
 
 extern __typeof (bcopy)   __bcopy_ppc attribute_hidden;
 extern __typeof (memmove) __memmove_ppc attribute_hidden;
diff --git a/sysdeps/powerpc/powerpc64/multiarch/bcopy.c b/sysdeps/powerpc/powerpc64/multiarch/bcopy.c
index 2aebfc0..1a7c909 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/bcopy.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/bcopy.c
@@ -17,6 +17,7 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <string.h>
+#include <strings.h>
 #include "init-arch.h"
 
 extern __typeof (bcopy) __bcopy_ppc attribute_hidden;
diff --git a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
index b9fef3f..41d1330 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
@@ -18,6 +18,7 @@
 
 #include <assert.h>
 #include <string.h>
+#include <strings.h>
 #include <wchar.h>
 #include <ldsodefs.h>
 #include <ifunc-impl-list.h>
diff --git a/sysdeps/s390/bzero.c b/sysdeps/s390/bzero.c
index fc0d46e..fc641e1 100644
--- a/sysdeps/s390/bzero.c
+++ b/sysdeps/s390/bzero.c
@@ -19,6 +19,7 @@
 #include <ifunc-memset.h>
 #if HAVE_MEMSET_IFUNC
 # include <string.h>
+# include <strings.h>
 # include <ifunc-resolve.h>
 
 # if HAVE_MEMSET_Z900_G5
diff --git a/sysdeps/s390/multiarch/ifunc-impl-list.c b/sysdeps/s390/multiarch/ifunc-impl-list.c
index e6195c6..0d94949 100644
--- a/sysdeps/s390/multiarch/ifunc-impl-list.c
+++ b/sysdeps/s390/multiarch/ifunc-impl-list.c
@@ -18,6 +18,7 @@
 
 #include <assert.h>
 #include <string.h>
+#include <strings.h>
 #include <wchar.h>
 #include <ifunc-impl-list.h>
 #include <ifunc-resolve.h>
diff --git a/sysdeps/sparc/sparc64/multiarch/bzero.c b/sysdeps/sparc/sparc64/multiarch/bzero.c
index ee50150..fc7af26 100644
--- a/sysdeps/sparc/sparc64/multiarch/bzero.c
+++ b/sysdeps/sparc/sparc64/multiarch/bzero.c
@@ -20,6 +20,7 @@
 #if IS_IN (libc)
 # define bzero __redirect_bzero
 # include <string.h>
+# include <strings.h>
 # undef bzero
 
 # include <sparc-ifunc.h>
diff --git a/sysdeps/sparc/sparc64/multiarch/ifunc-impl-list.c b/sysdeps/sparc/sparc64/multiarch/ifunc-impl-list.c
index ad79a26..2fa7a3a 100644
--- a/sysdeps/sparc/sparc64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/sparc/sparc64/multiarch/ifunc-impl-list.c
@@ -18,6 +18,7 @@
 
 #include <assert.h>
 #include <string.h>
+#include <strings.h>
 #include <wchar.h>
 #include <ldsodefs.h>
 #include <sysdep.h>