snapcast fails to compile with boost 1.81.0

[heitbaum]

Describe the bug
snapcast fails to compile with boost 1.81.0

• core::string_view no longer supports the .to_string() or .clear() extensions from Utility

boostorg/beast#2417
boostorg/beast#2418
boostorg/beast@9d23bec
boostorg/beast#2594

Steps to Reproduce

1. Install boost 1.81.0

Environment details

• OS: LibreELEC 11
• Snapcast version: 0.26.0
• Installed from a package, self compiled, ...
  • self compiled

Attach logfile if applicable
Generate logs with snapclient --logfilter debug or snapserver --logging.filter debug if possible and paste them in the following codeblock

/var/media/DATA/home-rudi/LibreELEC.kernel11/build.LibreELEC-ARMv7.arm-11.0-devel/toolchain/bin/armv7a-libreelec-linux-gnueabihf-g++ -march=armv7-a -mtune=cortex-a8 -mabi=aapcs-linux -Wno-psabi -Wa,-mno-warn-deprecated -mfloat-abi=hard -mfpu=neon-vfpv3 -Wall -pipe  -O2 -fomit-frame-pointer -DNDEBUG -pthread                       -I/var/media/DATA/home-rudi/LibreELEC.kernel11/build.LibreELEC-ARMv7.arm-11.0-devel/install_pkg/aixlog-1.5.0/usr/include                       -I/var/media/DATA/home-rudi/LibreELEC.kernel11/build.LibreELEC-ARMv7.arm-11.0-devel/install_pkg/asio-1.21.0/usr/include                       -I/var/media/DATA/home-rudi/LibreELEC.kernel11/build.LibreELEC-ARMv7.arm-11.0-devel/install_pkg/popl-1.3.0/usr/include -O2  -std=c++17 -Wall -Wextra -Wpedantic -Wno-unused-function -DBOOST_ERROR_CODE_HEADER_ONLY -DHAS_FLAC -DHAS_OGG -DHAS_VORBIS -DHAS_VORBIS_ENC -DHAS_OPUS -DHAS_SOXR -DVERSION=\"0.26.0\" -I. -I.. -I../common -DHAS_AVAHI -DHAS_DAEMON -DHAS_ALSA -pthread -c control_session_http.cpp -o control_session_http.o
control_session_http.cpp: In function 'std::string {anonymous}::path_cat(boost::beast::string_view, boost::beast::string_view)':
control_session_http.cpp:130:21: error: 'using string_view = boost::core::string_view' {aka 'class boost::core::basic_string_view<char>'} has no member named 'to_string'
  130 |         return path.to_string();
      |                     ^~~~~~~~~
control_session_http.cpp:131:31: error: 'using string_view = boost::core::string_view' {aka 'class boost::core::basic_string_view<char>'} has no member named 'to_string'
  131 |     std::string result = base.to_string();
      |                               ^~~~~~~~~
control_session_http.cpp: In lambda function:
control_session_http.cpp:174:26: error: 'using string_view = boost::core::string_view' {aka 'class boost::core::basic_string_view<char>'} has no member named 'to_string'
  174 |         res.body() = why.to_string();
      |                          ^~~~~~~~~
control_session_http.cpp: In lambda function:
control_session_http.cpp:185:48: error: 'using string_view = boost::core::string_view' {aka 'class boost::core::basic_string_view<char>'} has no member named 'to_string'
  185 |         res.body() = "The resource '" + target.to_string() + "' was not found.";
      |                                                ^~~~~~~~~
control_session_http.cpp: In lambda function:
control_session_http.cpp:207:52: error: 'using string_view = boost::core::string_view' {aka 'class boost::core::basic_string_view<char>'} has no member named 'to_string'
  207 |         res.body() = "An error occurred: '" + what.to_string() + "'";
      |                                                    ^~~~~~~~~
make[1]: *** [Makefile:109: control_session_http.o] Error 1
make[1]: Leaving directory '/var/media/DATA/home-rudi/LibreELEC.kernel11/build.LibreELEC-ARMv7.arm-11.0-devel/build/snapcast-0.26.0/server'
make: *** [Makefile:11: server] Error 2