On some linuxes, /usr/include belongs to GCC and the standard
libraries that work with clang are in /usr/lib/clang/8.0.0 or
some variation thereof.
This results in errors such as:
```
/../lib64/gcc/x86_64-pc-linux-gnu/8.3.0/../../../../include/c++/8.3.0/bits/cxxabi_init_exception.h:38:10: fatal error: 'stddef.h' file not found
```
during extraction.
pybind11 headers passed via the `pybind11_add_module` CMake
function can now be included as `SYSTEM` includes (`-isystem`).
This allows to set stricter (or experimental) warnings in
calling projects that might throw otherwise in headers
a user of pybind11 can not influence.
This updates the compilation to always apply hidden visibility to
resolve the issues with default visibility causing problems under debug
compilations. Moreover using the cmake property makes it easier for a
caller to override if absolutely needed for some reason.
For `pybind11_add_module` we use cmake to set the property; for the
targets, we append to compilation option to non-MSVC compilers.
Currently select_cxx_standard(), which sets PYBIND11_CPP_STANDARD when
not externally set, is only called from pybind11_add_module(), but the
embed target setup (which runs unconditionally) makes use of
${PYBIND11_CPP_STANDARD}, which isn't set yet. This commit removes the
`select_cxx_standard` function completely and just always runs the
standard detection code.
This also tweaks the detection code to not bothering checking for the
`-std=c++11` flag when the `-std=c++14` detection succeeded.
./tools/check-style.sh fails on stock OS X currently; this fixes it:
- use pipes directly rather than exec redirection (macOS's ancient
version of bash fails with the latter)
- macOS's ancient bash doesn't support '\e' escapes in `echo -e`;
replace with \033 instead
- BSD grep doesn't support GREP_COLORS, but does allow GREP_COLOR.
Adding both doesn't hurt GNU grep: GREP_COLOR is deprecated, and won't
be used when GREP_COLORS is set.
- BSD grep doesn't collapse multiple /'s in the listed filename, so
failures under `include/` would should up as
`include//pybind11/whatever.h`. This removes the / from the include
directory argument.
Minor other changes:
- The CRLF detection runs with -l, so GREP_COLORS wasn't doing
anything; removed it.
- The trailing whitespace test would trigger on CRLFs, but the CR would
result in messed up output. Changed the test to just match trailing
spaces and tabs, rather than all whitespace.
At this point, there is only a single test for interpreter basics.
Apart from embedding itself, having a C++ test framework will also
benefit the C++-side features by allowing them to be tested directly.
All targets provided by pybind11:
* pybind11::module - the existing target for creating extension modules
* pybind11::embed - new target for embedding the interpreter
* pybind11::pybind11 - common "base" target (headers only)
