Package: autoconf Version: 2.69-11 Severity: serious Originally debugged by Amos Jeffries in #907106:
$ cat configure.ac AC_INIT AC_PROG_CXX AC_LANG([C++]) AC_SEARCH_LIBS([__atomic_load_8],[atomic]) $ autoconf $ CXX=g++-7 ./configure checking whether the C++ compiler works... yes checking for C++ compiler default output file name... a.out checking for suffix of executables... checking whether we are cross compiling... no checking for suffix of object files... o checking whether we are using the GNU C++ compiler... yes checking whether g++-7 accepts -g... yes checking for library containing __atomic_load_8... -latomic $ CXX=g++-8 ./configure checking whether the C++ compiler works... yes checking for C++ compiler default output file name... a.out checking for suffix of executables... checking whether we are cross compiling... no checking for suffix of object files... o checking whether we are using the GNU C++ compiler... yes checking whether g++-8 accepts -g... yes checking for library containing __atomic_load_8... no $ config.log says: ... | #ifdef __cplusplus | extern "C" | #endif | char __atomic_load_8 (); | int | main () | { | return __atomic_load_8 (); | ; | return 0; | } configure:2326: g++-8 -o conftest -g -O2 conftest.cpp -latomic >&5 conftest.cpp:16:6: error: new declaration 'char __atomic_load_8()' ambiguates built-in declaration 'long unsigned int __atomic_load_8(const volatile void*, int)' [-fpermissive] char __atomic_load_8 (); ^~~~~~~~~~~~~~~ conftest.cpp: In function 'int main()': conftest.cpp:20:25: error: too few arguments to function 'long unsigned int __atomic_load_8(const volatile void*, int)' return __atomic_load_8 (); ^ ...