VHACD does not compile with musl libc

[jameswestman]

Godot version: 3bd49da
OS: Alpine Linux (Docker)

Issue description:
Godot Engine does not compile on Alpine (or other musl-based systems) due to the use of PTHREAD_MUTEX_RECURSIVE_NP in the third-party VHACD module. This appears to be a glibc-specific macro.

Here is the relevant log output:

[Initial build] Compiling ==> thirdparty/vhacd/src/VHACD.cpp
In file included from thirdparty/vhacd/inc/btScalar.h:190,
                 from thirdparty/vhacd/inc/btAlignedAllocator.h:23,
                 from thirdparty/vhacd/inc/btAlignedObjectArray.h:19,
                 from thirdparty/vhacd/inc/btConvexHullComputer.h:18,
                 from thirdparty/vhacd/src/VHACD.cpp:30:
thirdparty/vhacd/inc/vhacdMutex.h: In constructor 'VHACD::Mutex::Mutex()':
thirdparty/vhacd/inc/vhacdMutex.h:97:60: error: 'PTHREAD_MUTEX_RECURSIVE_NP' was not declared in this scope
         VHACD_VERIFY(pthread_mutexattr_settype(&mutexAttr, PTHREAD_MUTEX_RECURSIVE_NP) == 0);
                                                            ^~~~~~~~~~~~~~~~~~~~~~~~~~
thirdparty/vhacd/inc/vhacdMutex.h:97:9: note: in expansion of macro 'VHACD_VERIFY'
         VHACD_VERIFY(pthread_mutexattr_settype(&mutexAttr, PTHREAD_MUTEX_RECURSIVE_NP) == 0);
         ^~~~~~~~~~~~
thirdparty/vhacd/inc/vhacdMutex.h:97:60: note: suggested alternative: 'PTHREAD_MUTEX_RECURSIVE'
         VHACD_VERIFY(pthread_mutexattr_settype(&mutexAttr, PTHREAD_MUTEX_RECURSIVE_NP) == 0);
                                                            ^~~~~~~~~~~~~~~~~~~~~~~~~~
thirdparty/vhacd/inc/vhacdMutex.h:97:9: note: in expansion of macro 'VHACD_VERIFY'
         VHACD_VERIFY(pthread_mutexattr_settype(&mutexAttr, PTHREAD_MUTEX_RECURSIVE_NP) == 0);
         ^~~~~~~~~~~~
scons: *** [thirdparty/vhacd/src/VHACD.x11.tools.64.o] Error 1
scons: building terminated because of errors.

[bojidar-bg]

Same file, a bit higher up:

godot/thirdparty/vhacd/inc/vhacdMutex.h

Lines 74 to 76 in 3bd49da

	#if defined(__APPLE__)
	#define PTHREAD_MUTEX_RECURSIVE_NP PTHREAD_MUTEX_RECURSIVE
	#endif

I guess it tries to detect clang by checking for __APPLE__, but it evidently isn't enough?

[Calinou]

Pull request opened upstream: kmammou/v-hacd#70

[chiguireitor]

Something similar happens when cross-compiling from linux to windows with mingw.

thirdparty/vhacd/src/VHACD-ASYNC.cpp:307:7: error: 'thread' in namespace 'std' does not name a type
  307 |  std::thread      *mThread{ nullptr };
      |       ^~~~~~
thirdparty/vhacd/src/VHACD-ASYNC.cpp:10:1: note: 'std::thread' is defined in header '<thread>'; did you forget to '#include <thread>'?
    9 | #include <float.h>
  +++ |+#include <thread>
   10 | 
thirdparty/vhacd/src/VHACD-ASYNC.cpp:315:15: error: 'mutex' in namespace 'std' does not name a type
  315 |  mutable std::mutex      mMessageMutex;
      |               ^~~~~
thirdparty/vhacd/src/VHACD-ASYNC.cpp:10:1: note: 'std::mutex' is defined in header '<mutex>'; did you forget to '#include <mutex>'?
    9 | #include <float.h>
  +++ |+#include <mutex>
   10 | 
[ 50%] thirdparty/vhacd/src/VHACD-ASYNC.cpp: In member function 'virtual bool VHACD::MyHACD_API::Compute(const double*, uint32_t, const uint32_t*, uint32_t, const VHACD::IVHACD::Parameters&)':
thirdparty/vhacd/src/VHACD-ASYNC.cpp:53:3: error: 'mThread' was not declared in this scope; did you mean 'fread'?
   53 |   mThread = new std::thread([this, countPoints, countTriangles, _desc]()
      |   ^~~~~~~
      |   fread
thirdparty/vhacd/src/VHACD-ASYNC.cpp:53:17: error: expected type-specifier
   53 |   mThread = new std::thread([this, countPoints, countTriangles, _desc]()
      |                 ^~~
thirdparty/vhacd/src/VHACD-ASYNC.cpp:57:4: error: expected primary-expression before ')' token
   57 |   });
      |    ^
thirdparty/vhacd/src/VHACD-ASYNC.cpp: In member function 'virtual void VHACD::MyHACD_API::Cancel()':
thirdparty/vhacd/src/VHACD-ASYNC.cpp:166:7: error: 'mThread' was not declared in this scope; did you mean 'fread'?
  166 |   if (mThread)
      |       ^~~~~~~
      |       fread
thirdparty/vhacd/src/VHACD-ASYNC.cpp:169:11: error: type '<type error>' argument given to 'delete', expected pointer
  169 |    delete mThread;
      |           ^~~~~~~
thirdparty/vhacd/src/VHACD-ASYNC.cpp: In member function 'virtual void VHACD::MyHACD_API::Update(double, double, double, const char*, const char*)':
thirdparty/vhacd/src/VHACD-ASYNC.cpp:235:3: error: 'mMessageMutex' was not declared in this scope; did you mean 'mMessage'?
  235 |   mMessageMutex.lock();
      |   ^~~~~~~~~~~~~
      |   mMessage
thirdparty/vhacd/src/VHACD-ASYNC.cpp: In member function 'virtual void VHACD::MyHACD_API::Log(const char*)':
thirdparty/vhacd/src/VHACD-ASYNC.cpp:247:3: error: 'mMessageMutex' was not declared in this scope; did you mean 'mMessage'?
  247 |   mMessageMutex.lock();
      |   ^~~~~~~~~~~~~
      |   mMessage
thirdparty/vhacd/src/VHACD-ASYNC.cpp: In member function 'void VHACD::MyHACD_API::processPendingMessages() const':
thirdparty/vhacd/src/VHACD-ASYNC.cpp:267:4: error: 'mMessageMutex' was not declared in this scope; did you mean 'mMessage'?
  267 |    mMessageMutex.lock();
      |    ^~~~~~~~~~~~~
      |    mMessage
thirdparty/vhacd/src/VHACD-ASYNC.cpp:275:4: error: 'mMessageMutex' was not declared in this scope; did you mean 'mMessage'?
  275 |    mMessageMutex.lock();
      |    ^~~~~~~~~~~~~
      |    mMessage

[akien-mga]

@chiguireitor That's a different issue though. What version of MinGW do you use? It might be too old, we use mingw-w64 6.0.0 with GCC 9.1 successfully to build official Godot binaries for Windows from Linux. Your version doesn't seem to support C++11.

[chiguireitor]

i just followed instructions to install it on ubuntu 19.10.... i'm away from my build box, will check back when i'm at home.

If it makes a difference, it's using the latest master head, so stuff could be broken.

[chiguireitor]

Ok, finally made it work, had to switch alternative mingw from the -windows suffix to the -posix suffix, should be noted on the documentation tho

[jameswestman]

The original issue has not been fixed. I just tried compiling on Alpine Linux and it does not work.

[chiguireitor]

Did you try using posix threads? In ubuntu i know there's the update-alternative utilities, but dunno how it goes in Alpine.... also, Alpine uses Musl instead of Libc, so you might be having a slight incompatibility there.

[jameswestman]

Yes, the incompatibility is caused by Alpine's use of musl. The pull request above fixes the problem, but it needs to also be in Godot's copy.

[LinuxUserGD]

@chiguireitor Seems to be #40853 now