VLC @3.0.7.1: configure: error: C++ preprocessor "/usr/bin/clang++" fails sanity check

[stilwellweather]

Trying to build vlc 3.0.7.1 on my Mac running macOS 10.14.5 with Xcode 10.2.1 (10E1001) on the development git branch and VLC fails to configure

Error: Failed to configure VLC, consult /opt/local/var/macports/build/_opt_mports_macports-ports_multimedia_VLC/VLC/work/vlc-3.0.7.1/config.log
Error: Failed to configure VLC: configure failure: command execution failed
Error: See /opt/local/var/macports/logs/_opt_mports_macports-ports_multimedia_VLC/VLC/main.log for details.
Error: Follow https://guide.macports.org/#project.tickets to report a bug.
Error: Processing of port vlc failed

Log files after running port clean attached

[RJVB (René Bertin)]

What do you mean with "the development git branch"? Do you mean that you're running some kind of beta OS or toolchain version?

The failure:

configure:17889: checking how to run the C++ preprocessor
configure:17955: result: /usr/bin/clang++
configure:17975: /usr/bin/clang++ -I/opt/local/include -D__unix__=1 -Wno-unknown-pragmas -I/opt/local/lib/live/liveMedia/include -I/opt/local/var/macports/build/_opt_mports_macports-ports_multimedia_VLC/VLC/work/vlc-3.0.7.1/contrib/include conftest.cpp
conftest.cpp:41:8: error: unknown type name 'Syntax'
                     Syntax error
                     ^
conftest.cpp:41:20: error: expected ';' after top level declarator
                     Syntax error
                                 ^
                                 ;
2 errors generated.
configure:17975: $? = 1
configure: failed program was:
| /* confdefs.h */
| #define PACKAGE_NAME "vlc"
| #define PACKAGE_TARNAME "vlc"
| #define PACKAGE_VERSION "3.0.7.1"
| #define PACKAGE_STRING "vlc 3.0.7.1"
| #define PACKAGE_BUGREPORT ""
| #define PACKAGE_URL ""
| #define PACKAGE "vlc"
| #define VERSION "3.0.7.1"
| #define STDC_HEADERS 1
| #define HAVE_SYS_TYPES_H 1
| #define HAVE_SYS_STAT_H 1
| #define HAVE_STDLIB_H 1
| #define HAVE_STRING_H 1
| #define HAVE_MEMORY_H 1
| #define HAVE_STRINGS_H 1
| #define HAVE_INTTYPES_H 1
| #define HAVE_STDINT_H 1
| #define HAVE_UNISTD_H 1
| #define __EXTENSIONS__ 1
| #define _ALL_SOURCE 1
| #define _GNU_SOURCE 1
| #define _POSIX_PTHREAD_SEMANTICS 1
| #define _TANDEM_SOURCE 1
| #define _FORTIFY_SOURCE 2
| #define _FILE_OFFSET_BITS 64
| #define _THREAD_SAFE /**/
| #define __LIBVLC__ /**/
| #define WIN32_LEAN_AND_MEAN /**/
| #define YYTEXT_POINTER 1
| #define restrict __restrict
| #define VLC_WINSTORE_APP 0
| #define HAVE_DLFCN_H 1
| #define LT_OBJDIR ".libs/"
| /* end confdefs.h.  */
| #ifdef __STDC__
| # include <limits.h>
| #else
| # include <assert.h>
| #endif
| 		     Syntax error

Yes, there appears to be the words "Syntax error" appended to the conftest.cpp file, using tabs for indentation. I have no idea where this can come from...

EDIT: actually, it comes from the configure script, and is appended to catch a feature of a compiler on the Next OS (!), namely that cc -E pulls the output through the parser. The error suggests this feature also exists in the clang version of the Xcode you're using. Which is strange, because /methinks that lots of configure scripts are going to be failing.

Could you try with clang 5 or 6 from MacPorts (I have tested those myself, and I would avoid clang 8 because of a warning I saw somewhere)? If that works we may have to blacklist the clang version of your Xcode...

[stilwellweather]

When I say git development branch, I meant to say I installed MacPorts from git and didn't checkout a specific version. I tested the build with both versions of clang (5 and 6) as you suggested and it still failed.

[stilwellweather]

VLC with Clang 5

[stilwellweather]

VLC with Clang 5

[stilwellweather]

VLC with Clang 5

[stilwellweather]

VLC with Clang 6

[stilwellweather]

VLC with Clang 6

[RJVB (René Bertin)]

This has me flabbergasted. Doesn't VLC build on the 10.14 buildbot?

I don't see a trivial/proper way to disable the preprocessor check either. Ship a tweaked c.m4 file, maybe? The only easy thing I can think of ATM is a tweak to the portfile. Please do port edit VLC and then find the part where CXXCPP is set. Add a corresponding definition for CPP, e.g.

if {[vercmp [macports_version] 2.5.99] >= 0} {
    configure.env-append \
                    "CPP=${configure.cc} -E" \
                    "CXXCPP=${configure.cxx} -E"
} else {
    configure.env-append \
                    CPP="${configure.cc} -E" \
                    CXXCPP="${configure.cxx} -E"
}

Then, clean and attempt again

[RJVB (René Bertin)]

If that fails too, there's 1 more thing to try: replace ${configure.cc} above with clang-cpp-mp-N (where N is 5.0 or 6.0 or whatever clang version you're using).

[stilwellweather]

Good news. It looks like replacing ${configure.cc} with clang-cpp-mp-5.0 did the trick. It built and opened perfectly.

[cjones051073 (Chris Jones)]

${configure.cc} should refer to a C compiler, not a C++ compiler, which are what clang-cpp-mp-N are. So regardless of this works or not, its not really an acceptable fix.

[RJVB (René Bertin)]

Are you certain that clang-cpp is a C++ compiler and not a (C) preprocessor?

Also, please read more carefully. The tested fix is not replacing the value configure.cc, but replacing the use of configure.cc in the CPP env. variable.