Use libstdc++ instead of libc++ on Linux (we compile with clang anyway)

.github/workflows/build.yml

@@ -60,7 +60,7 @@ jobs:
         elif [[ "${{ runner.os }}" == "macOS" ]] ; then
           export gn_flags='extra_cflags=["-stdlib=libc++", "-mmacosx-version-min=10.9"] extra_cflags_cc=["-frtti"]'
         else
-          export gn_flags='cc="clang-10" cxx="clang++-10" extra_cflags_cc=["-stdlib=libc++"] extra_ldflags=["-stdlib=libc++"]'
+          export gn_flags='cc="clang-10" cxx="clang++-10"'
         fi
         gn gen out/${{ matrix.mode }}-${{ matrix.arch }} --args="is_debug=$is_debug is_official_build=$is_official skia_use_system_expat=false skia_use_system_icu=false skia_use_system_libjpeg_turbo=false skia_use_system_libpng=false skia_use_system_libwebp=false skia_use_system_zlib=false skia_use_sfntly=false skia_use_freetype=true skia_use_harfbuzz=true skia_pdf_subset_harfbuzz=true skia_use_system_freetype2=false skia_use_system_harfbuzz=false target_cpu=\"${{ matrix.arch }}\" $gn_flags"
     - name: Compiling