Attempting to rebuild with:
# rpmbuild --rebuild "libplacebo-6.292.1-1.fc39.src.rpm"

returns an error from the compiler (see below).

Possible missing build dependencies?

Reproducible: Always

Steps to Reproduce:
1. rpmbuild --rebuild "libplacebo-6.292.1-1.fc39.src.rpm"
Actual Results:  
FAILED: src/libplacebo.so.292.p/glsl_glslang.cc.o
g++ -Isrc/libplacebo.so.292.p -Isrc -I../src -Isrc/include -I../src/include -Isrc/opengl/include -I../src/opengl/include -Isrc/vulkan -Isrc/opengl/include/glad -fvisibility=hidden -fdi
agnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -std=c++11 -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-s
ecurity -Wp,-U_FORTIFY_SOURCE,-D_FORTIFY_SOURCE=3 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-an
nobin-cc1 -m64 -march=znver2 -mtune=znver2 -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -fPIC -pthread -DP
L_HAVE_PTHREAD -DPTHREAD_HAS_SETCLOCK -MD -MQ src/libplacebo.so.292.p/glsl_glslang.cc.o -MF src/libplacebo.so.292.p/glsl_glslang.cc.o.d -o src/libplacebo.so.292.p/glsl_glslang.cc.o -c
../src/glsl/glslang.cc
In file included from /usr/include/glslang/Include/Types.h:47,
                 from /usr/include/glslang/Include/intermediate.h:57,
                 from /usr/include/glslang/MachineIndependent/localintermediate.h:42,
                 from /usr/include/glslang/SPIRV/SpvTools.h:50,
                 from /usr/include/glslang/SPIRV/GlslangToSpv.h:42,
                 from ../src/glsl/glslang.cc:28:
/usr/include/glslang/Include/SpirvIntrinsics.h:120:10: error: ‘variant’ in namespace ‘std’ does not name a template type
  120 |     std::variant<const TIntermConstantUnion*, const TType*> value;
      |          ^~~~~~~
/usr/include/glslang/Include/SpirvIntrinsics.h:120:5: note: ‘std::variant’ is only available from C++17 onwards
  120 |     std::variant<const TIntermConstantUnion*, const TType*> value;
      |     ^~~
/usr/include/glslang/Include/SpirvIntrinsics.h: In constructor ‘glslang::TSpirvTypeParameter::TSpirvTypeParameter(const glslang::TIntermConstantUnion*)’:
/usr/include/glslang/Include/SpirvIntrinsics.h:100:60: error: ‘value’ was not declared in this scope
  100 |     TSpirvTypeParameter(const TIntermConstantUnion* arg) { value = arg; }
      |                                                            ^~~~~
/usr/include/glslang/Include/SpirvIntrinsics.h: In constructor ‘glslang::TSpirvTypeParameter::TSpirvTypeParameter(const glslang::TType*)’:
/usr/include/glslang/Include/SpirvIntrinsics.h:101:45: error: ‘value’ was not declared in this scope
  101 |     TSpirvTypeParameter(const TType* arg) { value = arg; }
      |                                             ^~~~~
/usr/include/glslang/Include/SpirvIntrinsics.h: In member function ‘const glslang::TIntermConstantUnion* glslang::TSpirvTypeParameter::getAsConstant() const’:
/usr/include/glslang/Include/SpirvIntrinsics.h:105:13: error: ‘value’ was not declared in this scope
  105 |         if (value.index() == 0)
      |             ^~~~~
/usr/include/glslang/Include/SpirvIntrinsics.h: In member function ‘const glslang::TType* glslang::TSpirvTypeParameter::getAsType() const’:
/usr/include/glslang/Include/SpirvIntrinsics.h:111:13: error: ‘value’ was not declared in this scope
  111 |         if (value.index() == 1)
      |             ^~~~~
ninja: build stopped: subcommand failed.
INFO: autodetecting backend as ninja
INFO: calculating backend command to run: /usr/bin/ninja -C /home/joseph/rpmbuild/BUILD/libplacebo-6.292.1/redhat-linux-build -j 12 -v
error: Bad exit status from /var/tmp/rpm-tmp.vEfAJL (%build)


Expected Results:  
Successful rebuilt package.