strdup: Assume the function exists.

* m4/strdup.m4 (gl_FUNC_STRDUP, gl_FUNC_STRDUP_POSIX): Don't test
whether strdup exists.
* modules/strdup (Files): Remove lib/strdup.c.
(configure.ac): Don't compile strdup.c.
* modules/strdup-posix (Depends-on, configure.ac): Don't test
ac_cv_func_strdup.
* doc/posix-functions/strdup.texi: Update.
* lib/unistr/u8-strdup.c: Assume HAVE_STRDUP is 1.
* modules/unistr/u8-strdup (Files): Remove lib/unistr/u-strdup.h.
(Depends-on): Remove unistr/u8-strlen.

ChangeLog

@@ -1,3 +1,17 @@
+2020-08-14  Bruno Haible  <bruno@clisp.org>
+
+	strdup: Assume the function exists.
+	* m4/strdup.m4 (gl_FUNC_STRDUP, gl_FUNC_STRDUP_POSIX): Don't test
+	whether strdup exists.
+	* modules/strdup (Files): Remove lib/strdup.c.
+	(configure.ac): Don't compile strdup.c.
+	* modules/strdup-posix (Depends-on, configure.ac): Don't test
+	ac_cv_func_strdup.
+	* doc/posix-functions/strdup.texi: Update.
+	* lib/unistr/u8-strdup.c: Assume HAVE_STRDUP is 1.
+	* modules/unistr/u8-strdup (Files): Remove lib/unistr/u-strdup.h.
+	(Depends-on): Remove unistr/u8-strlen.
+
 2020-08-13  Bruno Haible  <bruno@clisp.org>
 
 	sys_random: Work around an uClibc bug.

doc/posix-functions/strdup.texi

@@ -9,8 +9,6 @@ Gnulib module: strdup or strdup-posix
 Portability problems fixed by either Gnulib module @code{strdup} or @code{strdup-posix}:
 @itemize
 @item
-This function is missing on some old platforms.
-@item
 This function has no prototype in @code{<string.h>} on some old platforms.
 @end itemize
 

lib/unistr/u8-strdup.c

@@ -20,21 +20,10 @@
 /* Specification.  */
 #include "unistr.h"
 
-#if HAVE_STRDUP
-
-# include <string.h>
+#include <string.h>
 
 uint8_t *
 u8_strdup (const uint8_t *s)
 {
   return (uint8_t *) strdup ((const char *) s);
 }
-
-#else
-
-# define FUNC u8_strdup
-# define UNIT uint8_t
-# define U_STRLEN u8_strlen
-# include "u-strdup.h"
-
-#endif

m4/strdup.m4

@@ -1,4 +1,4 @@
-# strdup.m4 serial 13
+# strdup.m4 serial 14
 
 dnl Copyright (C) 2002-2020 Free Software Foundation, Inc.
 
@@ -9,7 +9,6 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_STRDUP],
 [
   AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
-  AC_CHECK_FUNCS_ONCE([strdup])
   AC_CHECK_DECLS_ONCE([strdup])
   if test $ac_cv_have_decl_strdup = no; then
     HAVE_DECL_STRDUP=0
@@ -20,11 +19,8 @@ AC_DEFUN([gl_FUNC_STRDUP_POSIX],
 [
   AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
   AC_REQUIRE([gl_CHECK_MALLOC_POSIX])
-  AC_CHECK_FUNCS_ONCE([strdup])
-  if test $ac_cv_func_strdup = yes; then
-    if test $gl_cv_func_malloc_posix != yes; then
-      REPLACE_STRDUP=1
-    fi
+  if test $gl_cv_func_malloc_posix != yes; then
+    REPLACE_STRDUP=1
   fi
   AC_CHECK_DECLS_ONCE([strdup])
   if test $ac_cv_have_decl_strdup = no; then

modules/strdup

@@ -8,7 +8,6 @@ Notice:
 This module is obsolete. But you may want to use the strdup-posix module.
 
 Files:
-lib/strdup.c
 m4/strdup.m4
 
 Depends-on:
@@ -16,10 +15,6 @@ string
 
 configure.ac:
 gl_FUNC_STRDUP
-if test $ac_cv_func_strdup = no; then
-  AC_LIBOBJ([strdup])
-  gl_PREREQ_STRDUP
-fi
 gl_STRING_MODULE_INDICATOR([strdup])
 
 Makefile.am:

modules/strdup-posix

@@ -7,11 +7,11 @@ m4/strdup.m4
 
 Depends-on:
 string
-malloc-posix    [test $ac_cv_func_strdup = no || test $REPLACE_STRDUP = 1]
+malloc-posix    [test $REPLACE_STRDUP = 1]
 
 configure.ac:
 gl_FUNC_STRDUP_POSIX
-if test $ac_cv_func_strdup = no || test $REPLACE_STRDUP = 1; then
+if test $REPLACE_STRDUP = 1; then
   AC_LIBOBJ([strdup])
   gl_PREREQ_STRDUP
 fi

modules/unistr/u8-strdup

@@ -3,11 +3,9 @@ Copy UTF-8 string.
 
 Files:
 lib/unistr/u8-strdup.c
-lib/unistr/u-strdup.h
 
 Depends-on:
 unistr/base
-unistr/u8-strlen
 
 configure.ac:
 AC_CHECK_FUNCS_ONCE([strdup])