string: Fix errors in C++ mode on glibc systems with clang

[Bruno Haible]

Building a complete gnulib testdir on a glibc system with clang 13, I see
these errors:

../gllib/string.h:745:1: error: reference to overloaded function could not be 
resolved; did you mean to call it?
../gllib/string.h:829:1: error: reference to overloaded function could not be 
resolved; did you mean to call it?
../gllib/string.h:859:1: error: reference to overloaded function could not be 
resolved; did you mean to call it?
../gllib/string.h:963:1: error: reference to overloaded function could not be 
resolved; did you mean to call it?
../gllib/string.h:1166:1: error: reference to overloaded function could not be 
resolved; did you mean to call it?
../gllib/string.h:1274:1: error: reference to overloaded function could not be 
resolved; did you mean to call it?
../gllib/string.h:1323:1: error: reference to overloaded function could not be 
resolved; did you mean to call it?

This patch fixes it.


2022-04-13  Bruno Haible  <bruno@clisp.org>

        string: Fix errors in C++ mode on glibc systems with clang.
        * lib/string.in.h (memchr, memrchr, rawmemchr, strchrnul, strpbrk,
        strstr, strcasestr): Use _GL_CXXALIASWARN1 also with clang, and add
        exception specification.

diff --git a/lib/string.in.h b/lib/string.in.h
index c9432948c1..b818ae9cdf 100644
--- a/lib/string.in.h
+++ b/lib/string.in.h
@@ -230,10 +230,11 @@ _GL_CXXALIAS_SYS_CAST2 (memchr,
                         void const *, (void const *__s, int __c, size_t __n));
 # endif
 # if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 10) && !defined __UCLIBC__) \
-     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
-_GL_CXXALIASWARN1 (memchr, void *, (void *__s, int __c, size_t __n));
+     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4) \
+         || defined __clang__)
+_GL_CXXALIASWARN1 (memchr, void *, (void *__s, int __c, size_t __n) throw ());
 _GL_CXXALIASWARN1 (memchr, void const *,
-                   (void const *__s, int __c, size_t __n));
+                   (void const *__s, int __c, size_t __n) throw ());
 # elif __GLIBC__ >= 2
 _GL_CXXALIASWARN (memchr);
 # endif
@@ -315,9 +316,10 @@ _GL_CXXALIAS_SYS_CAST2 (memrchr,
                         void *, (void const *, int, size_t),
                         void const *, (void const *, int, size_t));
 # if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 10) && !defined __UCLIBC__) \
-     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
-_GL_CXXALIASWARN1 (memrchr, void *, (void *, int, size_t));
-_GL_CXXALIASWARN1 (memrchr, void const *, (void const *, int, size_t));
+     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4) \
+         || defined __clang__)
+_GL_CXXALIASWARN1 (memrchr, void *, (void *, int, size_t) throw ());
+_GL_CXXALIASWARN1 (memrchr, void const *, (void const *, int, size_t) throw 
());
 # else
 _GL_CXXALIASWARN (memrchr);
 # endif
@@ -345,9 +347,11 @@ _GL_CXXALIAS_SYS_CAST2 (rawmemchr,
                         void *, (void const *__s, int __c_in),
                         void const *, (void const *__s, int __c_in));
 # if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 10) && !defined __UCLIBC__) \
-     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
-_GL_CXXALIASWARN1 (rawmemchr, void *, (void *__s, int __c_in));
-_GL_CXXALIASWARN1 (rawmemchr, void const *, (void const *__s, int __c_in));
+     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4) \
+         || defined __clang__)
+_GL_CXXALIASWARN1 (rawmemchr, void *, (void *__s, int __c_in) throw ());
+_GL_CXXALIASWARN1 (rawmemchr, void const *,
+                   (void const *__s, int __c_in) throw ());
 # else
 _GL_CXXALIASWARN (rawmemchr);
 # endif
@@ -449,9 +453,11 @@ _GL_CXXALIAS_SYS_CAST2 (strchrnul,
                         char const *, (char const *__s, int __c_in));
 # endif
 # if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 10) && !defined __UCLIBC__) \
-     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
-_GL_CXXALIASWARN1 (strchrnul, char *, (char *__s, int __c_in));
-_GL_CXXALIASWARN1 (strchrnul, char const *, (char const *__s, int __c_in));
+     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4) \
+         || defined __clang__)
+_GL_CXXALIASWARN1 (strchrnul, char *, (char *__s, int __c_in) throw ());
+_GL_CXXALIASWARN1 (strchrnul, char const *,
+                   (char const *__s, int __c_in) throw ());
 # else
 _GL_CXXALIASWARN (strchrnul);
 # endif
@@ -651,10 +657,11 @@ _GL_CXXALIAS_SYS_CAST2 (strpbrk,
                         char *, (char const *__s, char const *__accept),
                         const char *, (char const *__s, char const *__accept));
 # if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 10) && !defined __UCLIBC__) \
-     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
-_GL_CXXALIASWARN1 (strpbrk, char *, (char *__s, char const *__accept));
+     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4) \
+         || defined __clang__)
+_GL_CXXALIASWARN1 (strpbrk, char *, (char *__s, char const *__accept) throw 
());
 _GL_CXXALIASWARN1 (strpbrk, char const *,
-                   (char const *__s, char const *__accept));
+                   (char const *__s, char const *__accept) throw ());
 # elif __GLIBC__ >= 2
 _GL_CXXALIASWARN (strpbrk);
 # endif
@@ -759,10 +766,12 @@ _GL_CXXALIAS_SYS_CAST2 (strstr,
                         const char *, (const char *haystack, const char 
*needle));
 # endif
 # if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 10) && !defined __UCLIBC__) \
-     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
-_GL_CXXALIASWARN1 (strstr, char *, (char *haystack, const char *needle));
+     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4) \
+         || defined __clang__)
+_GL_CXXALIASWARN1 (strstr, char *,
+                   (char *haystack, const char *needle) throw ());
 _GL_CXXALIASWARN1 (strstr, const char *,
-                   (const char *haystack, const char *needle));
+                   (const char *haystack, const char *needle) throw ());
 # elif __GLIBC__ >= 2
 _GL_CXXALIASWARN (strstr);
 # endif
@@ -808,10 +817,12 @@ _GL_CXXALIAS_SYS_CAST2 (strcasestr,
                         const char *, (const char *haystack, const char 
*needle));
 # endif
 # if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 10) && !defined __UCLIBC__) \
-     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
-_GL_CXXALIASWARN1 (strcasestr, char *, (char *haystack, const char *needle));
+     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4) \
+         || defined __clang__)
+_GL_CXXALIASWARN1 (strcasestr, char *,
+                   (char *haystack, const char *needle) throw ());
 _GL_CXXALIASWARN1 (strcasestr, const char *,
-                   (const char *haystack, const char *needle));
+                   (const char *haystack, const char *needle) throw ());
 # else
 _GL_CXXALIASWARN (strcasestr);
 # endif