build-libwebrtc: do not use custom libcxx (#207)

Not needed with clang

Author: jmillan

.github/workflows/build-libwebrtc.yml

@@ -29,11 +29,11 @@ jobs:
                 build:
                     - os: ubuntu-24.04
                       artifact: libwebrtc-linux-x64
-                      gn_args: is_debug=false is_component_build=false is_clang=true rtc_include_tests=false rtc_use_h264=true treat_warnings_as_errors=false use_rtti=true use_custom_libcxx=false
+                      gn_args: is_debug=false is_component_build=false is_clang=true rtc_include_tests=false rtc_use_h264=true treat_warnings_as_errors=false use_rtti=true
 
                     - os: macos-15
                       artifact: libwebrtc-macos-arm64
-                      gn_args: is_debug=false is_component_build=false is_clang=true rtc_include_tests=false rtc_use_h264=true treat_warnings_as_errors=false use_rtti=true use_custom_libcxx=false
+                      gn_args: is_debug=false is_component_build=false is_clang=true rtc_include_tests=false rtc_use_h264=true treat_warnings_as_errors=false use_rtti=true
 
         name: Build (${{ matrix.build.os }})
         runs-on: ${{ matrix.build.os }}