[Ubuntu 18.04.5 LTS - clang++-10 - ninja] Something wrong with my OpenEXR version?

I'm on Ubuntu:



```

$ lsb_release -a

LSB Version:	security-9.20170808ubuntu1-noarch

Distributor ID:	Ubuntu

Description:	Ubuntu 18.04.5 LTS

Release:	18.04

Codename:	bionic

```



I did compile pbrt-v4 (revision 1e6c0e5) before and I'm still able to compile that exact same version, but not the last version in the master branch (f739c88):



```

$ mkdir build

$ cd build/

$ export CXX=clang++-10

$ export CC=clang-10

$ cmake -GNinja ..

-- The CXX compiler identification is Clang 10.0.0

-- The C compiler identification is Clang 10.0.0

-- Detecting CXX compiler ABI info

-- Detecting CXX compiler ABI info - done

-- Check for working CXX compiler: /usr/bin/clang++-10 - skipped

-- Detecting CXX compile features

-- Detecting CXX compile features - done

-- Detecting C compiler ABI info

-- Detecting C compiler ABI info - done

-- Check for working C compiler: /usr/bin/clang-10 - skipped

-- Detecting C compile features

-- Detecting C compile features - done

-- Setting build type to 'Release' as none was specified.

-- Found Git: /usr/bin/git (found version "2.17.1") 

-- OpenEXR at commit: 5cfb5dab6dfada731586b0281bdb15ee75e26782

-- Ptex at commit: 4cd8e9a6db2b06e478dfbbd8c26eb6df97f84483

-- double-conversion at commit: cc1f75a114aca8d2af69f73a5a959aecbab0e87a

-- filesystem at commit: f45da753728cde9b1c380b343e41c8b1ca6498d7

-- stb at commit: b42009b3b9d4ca35bc703f5310eedc74f584be58

-- OpenVDB at commit: 1c306bcaf7e9f7d52525bab716202bd4f7fff5d1

-- zlib at commit: 54d591eabf9fe0e84c725638f8d5d8d202a093fa

-- Looking for pthread.h

-- Looking for pthread.h - found

-- Performing Test CMAKE_HAVE_LIBC_PTHREAD

-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Failed

-- Looking for pthread_create in pthreads

-- Looking for pthread_create in pthreads - not found

-- Looking for pthread_create in pthread

-- Looking for pthread_create in pthread - found

-- Found Threads: TRUE  

-- Found ZLIB: /usr/lib/x86_64-linux-gnu/libz.so (found version "1.2.11") 

-- Could NOT find Imath (missing: Imath_DIR)

-- Could NOT find IlmBase (missing: IlmBase_DIR)

-- Could NOT find OpenEXR (missing: OpenEXR_DIR)

-- Found PkgConfig: /usr/bin/pkg-config (found version "0.29.1") 

-- Found OpenEXR: /usr/include  

-- Found OpenEXR version 2.2.0

-- Could NOT find Doxygen (missing: DOXYGEN_EXECUTABLE) 

-- Unable to find -lprofiler

-- Looking for a CUDA compiler

-- Looking for a CUDA compiler - /usr/local/cuda/bin/nvcc

-- Found CUDA: /usr/local/cuda (found version "11.0") 

-- Found CUDA: 11.0

CMake Warning at CMakeLists.txt:153 (message):

  Found CUDA but PBRT_OPTIX7_PATH is not set.  Disabling GPU compilation.





-- Performing Test COMPILER_SUPPORTS_MARCH_NATIVE

-- Performing Test COMPILER_SUPPORTS_MARCH_NATIVE - Success

-- Performing Test HAVE_MMAP

-- Performing Test HAVE_MMAP - Success

-- Performing Test HAS_INTRIN_H

-- Performing Test HAS_INTRIN_H - Failed

-- Performing Test HAVE_DECLSPEC_NOINLINE

-- Performing Test HAVE_DECLSPEC_NOINLINE - Failed

-- Performing Test HAVE_ATTRIBUTE_NOINLINE

-- Performing Test HAVE_ATTRIBUTE_NOINLINE - Success

-- Performing Test HAVE__ALIGNED_MALLOC

-- Performing Test HAVE__ALIGNED_MALLOC - Failed

-- Performing Test HAVE_POSIX_MEMALIGN

-- Performing Test HAVE_POSIX_MEMALIGN - Success

-- Performing Test INT64_IS_OWN_TYPE

-- Performing Test INT64_IS_OWN_TYPE - Failed

-- Configuring done

-- Generating done

-- Build files have been written to: /home/jan/git/github/pbrt-v4/build

$ ninja

...

FAILED: CMakeFiles/pbrt_lib.dir/src/pbrt/util/image.cpp.o 

/usr/bin/clang++-10 -DPBRT_HAVE_MMAP -DPBRT_HAVE_POSIX_MEMALIGN -DPBRT_IS_LINUX -DPBRT_NOINLINE="__attribute__((noinline))" -DPTEX_STATIC -I../src -I../src/ext -I../src/ext/stb -I/usr/include/OpenEXR -I../src/ext/filesystem -I../src/ext/ptex/src/ptex -I../src/ext/double-conversion -I../src/ext/openvdb/nanovdb -I. -O3 -DNDEBUG -march=native -std=gnu++17 -MD -MT CMakeFiles/pbrt_lib.dir/src/pbrt/util/image.cpp.o -MF CMakeFiles/pbrt_lib.dir/src/pbrt/util/image.cpp.o.d -o CMakeFiles/pbrt_lib.dir/src/pbrt/util/image.cpp.o -c ../src/pbrt/util/image.cpp

In file included from ../src/pbrt/util/image.cpp:22:

In file included from /usr/include/OpenEXR/ImfChromaticitiesAttribute.h:46:

In file included from /usr/include/OpenEXR/ImfAttribute.h:48:

In file included from /usr/include/OpenEXR/ImfXdr.h:108:

/usr/include/OpenEXR/half.h:462:2: error: ISO C++17 does not allow 'register' storage class specifier [-Wregister]

        register int e = (x.i >> 23) & 0x000001ff;

        ^~~~~~~~~

```



Did anybody else see that problem? What's the best way to proceed?

[]