sys-include/newlib.h

["Jon Beniston" <jon at beniston dot com>]

Hi,

I'm compiling newlib 2.4.0 with gcc 6.1 configured as a cross compiler. In
order for some gcc libc support to be built, I need to configure with
--with-headers=/path/newlib/libc/include/

This results in the .h files from that directory being copied to
target/sys-include. GCC's built in search path searches target/sys-include
before target/include. This results in a bit of a problem when compiling C++
code, as target/sys-include/newlib.h differs from target/include/newlib.h

target/sys-include/newlib.h is an otherwise empty file that just says:

/* dummy file for external tools to use.  Real file is created by
   newlib configuration. */

Whereas target/include/newlib.h includes the newlib configuration macros,
such as:

#define _HAVE_LONG_DOUBLE 1

This causes an error "'::strtold' has not been declared"  when compiling C++
code, as the prototype for this function in stdlib.h, depends on this macro:

#ifdef _HAVE_LONG_DOUBLE
extern long double strtold (const char *__restrict, char **__restrict);
#endif /* _HAVE_LONG_DOUBLE */

Which is not defined as  target/sys-include/newlib.h is included instead of
target/include/newlib.h

The same applies to _newlib_version.h too.

And ideas on the best way to resolve this? Is it a gcc or newlib problem or
user error?

Thanks,
Jon