checking for strerror_r returning char *... yes
configure: error:
Your compiler offers a strerror_r() function, but test programs redeclaring it
as returning int and char *, respectively, both compile successfully.  The
former is what the Single Unix Specification SUSv3 dictates, and the latter is
an older GNU libc function.  At least one of these tests should have failed,
since there can't be two versions of this function taking the same arguments but
returning different types.

As a result of this ambiguity, the configure script was unable to determine
which version of the function is correct.  You may need to use less permissive
compiler options so that at least one of the alternatives will fail to compile.

See the config.log for more details; search for strerror_r to find the relevant
snippets.  If all else fails, consider compiling a non-threadsafe version of
libpqxx using the configure script's --disable-thread-safety option.

+ exit 3