groff @1.22.4: build fails due to math.h name collision

[kencu (Ken)]

  CXX      src/libs/libgroff/libgroff_a-device.o
In file included from src/libs/libgroff/assert.cpp:20:
In file included from /opt/local/libexec/llvm-9.0/bin/../include/c++/v1/stdlib.h:100:
./lib/math.h:38:3: error: "Please include config.h first."
 #error "Please include config.h first."
  ^
./lib/math.h:40:1: error: unknown type name '_GL_INLINE_HEADER_BEGIN'
_GL_INLINE_HEADER_BEGIN
^
./lib/math.h:1537:1: error: expected unqualified-id
_GL_CXXALIAS_SYS (frexp, double, (double x, int *expptr));
^
./lib/stdio.h:344:5: note: expanded from macro '_GL_CXXALIAS_SYS'
    _GL_EXTERN_C int _gl_cxxalias_dummy
    ^
./lib/stdio.h:234:30: note: expanded from macro '_GL_EXTERN_C'
# define _GL_EXTERN_C extern "C"
                             ^
In file included from src/libs/libgroff/assert.cpp:20:
In file included from /opt/local/libexec/llvm-9.0/bin/../include/c++/v1/stdlib.h:100:
./lib/math.h:2888:1: error: unknown type name '_GL_INLINE_HEADER_END'
_GL_INLINE_HEADER_END

but builds fine when I force the build compiler to clang-5.0:

 port -v installed groff
The following ports are currently installed:
  groff @1.22.4_2 (active) platform='darwin 10' archs='x86_64' date='2019-11-30T13:25:24-0800'

[kencu (Ken)]

exactly the same error occurs on Mojave with clang-9.0 as well.

[kencu (Ken)]

clang-8.0 works.

[kencu (Ken)]

In 0cd324405d720d64707f9ecd83fa9bec937a925f/macports-ports (master):

groff: blacklist clang-9.0+

not presently building with these compilers
see: #59783

[kencu (Ken)]

was going to add clang-devel, ergo the 9.0+, but in the end, did not.

I see JMR is working on this separately, hopefully will find the real fix.

[jmroot (Joshua Root)]

It has a header called math.h in the search path (-I./lib). It can only be by pure luck that this hasn't caused problems with earlier compiler versions.

[ryandesign (Ryan Carsten Schmidt)]

Here is another distribution's fix for this issue:

​https://github.com/openembedded/openembedded-core/blob/master/meta/recipes-extended/groff/files/0001-Include-config.h.patch

[ryandesign (Ryan Carsten Schmidt)]

@jmroot see comment above