>> configure:17517: gcc -c
>> -I/Users/travis/ttfautohint-build/local/include -g -O2 conftest.c >&5
>> conftest.c:145:13: error: use of undeclared identifier 'max_align_t'
>
> Evidently the stddef.h found by the above command does not define
> max_align_t, whereas the stddef.h found by the command 'CXX main.o'
> in
> <https://travis-ci.org/source-foundry/ttfautohint-build/jobs/269031319#L3401>
> does define max_align_t. Can you investigate why this is so?
> Perhaps CXX uses different -I options, or perhaps stddef.h does not
> define max_align_t if C++.
I suspect that the used clang version doesn't activate C11 support by
default, while C++11 is available.
Right now I only have the `stddef.h' file of a later XCode version
(from 2015); however, looking at the copyright notice it seems that it
is unchanged. It contains the following.
#if (defined (__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) \
|| (defined(__cplusplus) && __cplusplus >= 201103L)
typedef long double max_align_t;
#endif
Chris, do you have a chance to check
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/6.1.0/include/stddef.h
of an OS X 10.10 Travis run whether the definition is identical?
> Ideally 'configure' should be using the same compiler and options as
> 'make'; when that isn't true, there can be trouble.
Sounds sensible. However, how to do that correctly? The
`max_align_t' test is part of gnulib, I don't ask for it. Shall I
simply add
AC_LANG_PUSH([C++])
right before the call to
gl_INIT
in my `configure.ac' file? Note that I also have
AX_CXX_COMPILE_STDCXX([11],,[optional])
to activate C++11 if available.
Werner
