Paddle compile error when -DWITH_CINN=ON on Hygon DCU about paddle

[risemeup1]

这个是C++17标准的用法，std::clamp，检查下你编译的时候是不是用的C++14？

[DongBaiYue]

@risemeup1 确实是因为c++版本，不过改成c++17还是出错。
原因在cmake/hip.cmake

if(WITH_CINN)
  list(APPEND HIP_CXX_FLAGS -std=c++14)
else()
  list(APPEND HIP_CXX_FLAGS -std=c++17)
endif()

改成-std=c++17，出现了另一个错误：

[ 97%] Building CXX object paddle/fluid/inference/analysis/passes/CMakeFiles/convert_to_mixed_precision.dir/convert_to_mixed_precision.cc.o
/usr/bin/ld: ../../../../libcinnapi.so: undefined reference to `absl::lts_20210324::strings_internal::CalculateBase64EscapedLenInternal(unsigned long, bool)'
/usr/bin/ld: ../../../../libcinnapi.so: undefined reference to `absl::lts_20210324::raw_logging_internal::RawLog(absl::lts_20210324::LogSeverity, char const*, int, char const*, ...)'
/usr/bin/ld: ../../../../libcinnapi.so: undefined reference to `absl::lts_20210324::strings_internal::kBase64Chars'
/usr/bin/ld: ../../../../libcinnapi.so: undefined reference to `absl::lts_20210324::strings_internal::Base64EscapeInternal(unsigned char const*, unsigned long, char*, unsigned long, char const*, bool)'
/usr/bin/ld: ../../../../libcinnapi.so: undefined reference to `absl::lts_20210324::strings_internal::EncodeUTF8Char(char*, char32_t)

[danleifeng]

CINN目前开源的代码还未支持DCU编译，后续功能会开源，请关注，谢谢