stdlib: Avoid syntax errors in libstdc++ header files

[Bruno Haible]

After yesterday's correction of stdlib.h in C++ mode, the CI reports a
compilation error on Solaris 11 OmniOS:

g++ -DHAVE_CONFIG_H -DEXEEXT=\"\" -DEXEEXT=\"\" -I. -I../../gltests -I..  
-DGNULIB_STRICT_CHECKING=1 -DIN_GNULIB_TESTS=1 -I. -I../../gltests -I.. 
-I../../gltests/.. -I../gllib -I../../gltests/../gllib 
-I/home/bruno/prefix64/include -I/opt/ooce/include -Wall -D_REENTRANT  
-Wno-error -g -O2 -MT test-nullptr-c++.o -MD -MP -MF $depbase.Tpo -c -o 
test-nullptr-c++.o ../../gltests/test-nullptr-c++.cc &&\
mv -f $depbase.Tpo $depbase.Po
In file included from ../gllib/pthread.h:62,
                 from 
/opt/gcc-9/include/c++/9.3.0/x86_64-pc-solaris2.11/bits/gthr-default.h:35,
                 from 
/opt/gcc-9/include/c++/9.3.0/x86_64-pc-solaris2.11/bits/gthr.h:148,
                 from /opt/gcc-9/include/c++/9.3.0/ext/atomicity.h:35,
                 from /opt/gcc-9/include/c++/9.3.0/bits/ios_base.h:39,
                 from /opt/gcc-9/include/c++/9.3.0/ios:42,
                 from /opt/gcc-9/include/c++/9.3.0/ostream:38,
                 from /opt/gcc-9/include/c++/9.3.0/iostream:39,
                 from ../../gltests/test-nullptr-c++.cc:25:
/opt/gcc-9/include/c++/9.3.0/bits/basic_string.h: In function 'int 
std::__cxx11::stoi(const string&, std::size_t*, int)':
/opt/gcc-9/include/c++/9.3.0/bits/basic_string.h:6504:47: error: 'rpl_strtol' 
is not a member of 'std'; did you mean 'strtol'?
 6504 |   { return __gnu_cxx::__stoa<long, int>(&std::strtol, "stoi", 
__str.c_str(),
      |                                               ^~~~~~
/opt/gcc-9/include/c++/9.3.0/bits/basic_string.h: In function 'long int 
std::__cxx11::stol(const string&, std::size_t*, int)':
/opt/gcc-9/include/c++/9.3.0/bits/basic_string.h:6509:36: error: 'rpl_strtol' 
is not a member of 'std'; did you mean 'strtol'?
 6509 |   { return __gnu_cxx::__stoa(&std::strtol, "stol", __str.c_str(),
      |                                    ^~~~~~
/opt/gcc-9/include/c++/9.3.0/bits/basic_string.h: In function 'long unsigned 
int std::__cxx11::stoul(const string&, std::size_t*, int)':
/opt/gcc-9/include/c++/9.3.0/bits/basic_string.h:6514:36: error: 'rpl_strtoul' 
is not a member of 'std'; did you mean 'strtoul'?
 6514 |   { return __gnu_cxx::__stoa(&std::strtoul, "stoul", __str.c_str(),
      |                                    ^~~~~~~
/opt/gcc-9/include/c++/9.3.0/bits/basic_string.h: In function 'long long int 
std::__cxx11::stoll(const string&, std::size_t*, int)':
/opt/gcc-9/include/c++/9.3.0/bits/basic_string.h:6519:36: error: 'rpl_strtoll' 
is not a member of 'std'; did you mean 'rpl_strtoll'?
 6519 |   { return __gnu_cxx::__stoa(&std::strtoll, "stoll", __str.c_str(),
      |                                    ^~~~~~~
In file included from /usr/include/sys/time.h:489,
                 from ../gllib/sys/time.h:46,
                 from /usr/include/sys/select.h:53,
                 from ../gllib/sys/select.h:43,
                 from /usr/include/sys/types.h:640,
                 from ../gllib/sys/types.h:46,
                 from ../gllib/stdio.h:83,
                 from /usr/include/iso/wchar_iso.h:54,
                 from 
/opt/gcc-9/lib/gcc/x86_64-pc-solaris2.11/9.3.0/include-fixed/wchar.h:40,
                 from ../gllib/wchar.h:80,
                 from /opt/gcc-9/include/c++/9.3.0/cwchar:44,
                 from /opt/gcc-9/include/c++/9.3.0/bits/postypes.h:40,
                 from /opt/gcc-9/include/c++/9.3.0/iosfwd:40,
                 from /opt/gcc-9/include/c++/9.3.0/ios:38,
                 from /opt/gcc-9/include/c++/9.3.0/ostream:38,
                 from /opt/gcc-9/include/c++/9.3.0/iostream:39,
                 from ../../gltests/test-nullptr-c++.cc:25:
../gllib/stdlib.h:2309:1: note: 'rpl_strtoll' declared here
 2309 | _GL_FUNCDECL_RPL (strtoll, long long,
      | ^~~~~~~~~~~~~~~~
In file included from ../gllib/pthread.h:62,
                 from 
/opt/gcc-9/include/c++/9.3.0/x86_64-pc-solaris2.11/bits/gthr-default.h:35,
                 from 
/opt/gcc-9/include/c++/9.3.0/x86_64-pc-solaris2.11/bits/gthr.h:148,
                 from /opt/gcc-9/include/c++/9.3.0/ext/atomicity.h:35,
                 from /opt/gcc-9/include/c++/9.3.0/bits/ios_base.h:39,
                 from /opt/gcc-9/include/c++/9.3.0/ios:42,
                 from /opt/gcc-9/include/c++/9.3.0/ostream:38,
                 from /opt/gcc-9/include/c++/9.3.0/iostream:39,
                 from ../../gltests/test-nullptr-c++.cc:25:
/opt/gcc-9/include/c++/9.3.0/bits/basic_string.h: In function 'long long 
unsigned int std::__cxx11::stoull(const string&, std::size_t*, int)':
/opt/gcc-9/include/c++/9.3.0/bits/basic_string.h:6524:36: error: 'rpl_strtoull' 
is not a member of 'std'; did you mean 'rpl_strtoull'?
 6524 |   { return __gnu_cxx::__stoa(&std::strtoull, "stoull", __str.c_str(),
      |                                    ^~~~~~~~
In file included from /usr/include/sys/time.h:489,
                 from ../gllib/sys/time.h:46,
                 from /usr/include/sys/select.h:53,
                 from ../gllib/sys/select.h:43,
                 from /usr/include/sys/types.h:640,
                 from ../gllib/sys/types.h:46,
                 from ../gllib/stdio.h:83,
                 from /usr/include/iso/wchar_iso.h:54,
                 from 
/opt/gcc-9/lib/gcc/x86_64-pc-solaris2.11/9.3.0/include-fixed/wchar.h:40,
                 from ../gllib/wchar.h:80,
                 from /opt/gcc-9/include/c++/9.3.0/cwchar:44,
                 from /opt/gcc-9/include/c++/9.3.0/bits/postypes.h:40,
                 from /opt/gcc-9/include/c++/9.3.0/iosfwd:40,
                 from /opt/gcc-9/include/c++/9.3.0/ios:38,
                 from /opt/gcc-9/include/c++/9.3.0/ostream:38,
                 from /opt/gcc-9/include/c++/9.3.0/iostream:39,
                 from ../../gltests/test-nullptr-c++.cc:25:
../gllib/stdlib.h:2392:1: note: 'rpl_strtoull' declared here
 2392 | _GL_FUNCDECL_RPL (strtoull, unsigned long long,
      | ^~~~~~~~~~~~~~~~
gmake[4]: *** [Makefile:27303: test-nullptr-c++.o] Error 1

This patch fixes it.


2024-07-14  Bruno Haible  <bruno@clisp.org>

        stdlib: Avoid syntax errors in libstdc++ header files.
        * lib/stdlib.in.h: Include <string> before strtol, strtoll, strtoul, or
        strtoull gets defined as a macro.

diff --git a/lib/stdlib.in.h b/lib/stdlib.in.h
index 47a8856dc7..ac328eb5e7 100644
--- a/lib/stdlib.in.h
+++ b/lib/stdlib.in.h
@@ -117,6 +117,16 @@ struct random_data
 # include <unistd.h>
 #endif
 
+#if ((@GNULIB_STRTOL@ && @REPLACE_STRTOL@) || (@GNULIB_STRTOLL@ && 
@REPLACE_STRTOLL@) || (@GNULIB_STRTOUL@ && @REPLACE_STRTOUL@) || 
(@GNULIB_STRTOULL@ && @REPLACE_STRTOULL@)) && defined __cplusplus && !defined 
GNULIB_NAMESPACE && defined __GNUG__
+/* When strtol, strtoll, strtoul, or strtoull is going to be defined as a macro
+   below, this may cause compilation errors later in the libstdc++ header files
+   (that are part of GCC), such as:
+     error: 'rpl_strtol' is not a member of 'std'
+   To avoid this, include the relevant header files here, before these symbols
+   get defined as macros.  */
+# include <string>
+#endif
+
 /* _GL_ATTRIBUTE_DEALLOC (F, I) declares that the function returns pointers
    that can be freed by passing them as the Ith argument to the
    function F.  */