bootstrap build failure

[philberty]

/home/runner/work/gccrs/gccrs/gccrs-build/./prev-gcc/xg++ -B/home/runner/work/gccrs/gccrs/gccrs-build/./prev-gcc/ -B/usr/local/x86_64-pc-linux-gnu/bin/ -nostdinc++ -B/home/runner/work/gccrs/gccrs/gccrs-build/prev-x86_64-pc-linux-gnu/libstdc++-v3/src/.libs -B/home/runner/work/gccrs/gccrs/gccrs-build/prev-x86_64-pc-linux-gnu/libstdc++-v3/libsupc++/.libs  -I/home/runner/work/gccrs/gccrs/gccrs-build/prev-x86_64-pc-linux-gnu/libstdc++-v3/include/x86_64-pc-linux-gnu  -I/home/runner/work/gccrs/gccrs/gccrs-build/prev-x86_64-pc-linux-gnu/libstdc++-v3/include  -I/home/runner/work/gccrs/gccrs/libstdc++-v3/libsupc++ -L/home/runner/work/gccrs/gccrs/gccrs-build/prev-x86_64-pc-linux-gnu/libstdc++-v3/src/.libs -L/home/runner/work/gccrs/gccrs/gccrs-build/prev-x86_64-pc-linux-gnu/libstdc++-v3/libsupc++/.libs  -fno-PIE -c  -DIN_GCC_FRONTEND -g -O2 -fno-checking -gtoggle -DIN_GCC     -fno-exceptions -fno-rtti -fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings -Wcast-qual -Wmissing-format-attribute -Woverloaded-virtual -pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -Werror -fno-common  -DHAVE_CONFIG_H -I. -Irust -I../../gcc -I../../gcc/rust -I../../gcc/../include -I../../gcc/../libcpp/include -I../../gcc/../libcody  -I../../gcc/../libdecnumber -I../../gcc/../libdecnumber/bid -I../libdecnumber -I../../gcc/../libbacktrace   -o rust/rust-cfg-parser.o -MT rust/rust-cfg-parser.o -MMD -MP -MF rust/.deps/rust-cfg-parser.TPo -g -O2 -fno-checking -gtoggle -I ../../gcc/rust -I ../../gcc/rust/lex -I ../../gcc/rust/parse -I ../../gcc/rust/ast -I ../../gcc/rust/analysis -I ../../gcc/rust/backend -I ../../gcc/rust/expand -I ../../gcc/rust/hir/tree -I ../../gcc/rust/hir -I ../../gcc/rust/resolve -I ../../gcc/rust/util -I ../../gcc/rust/typecheck -I ../../gcc/rust/checks/lints -I ../../gcc/rust/checks/errors -I ../../gcc/rust/checks/errors/privacy -I ../../gcc/rust/util -I ../../gcc/rust/metadata ../../gcc/rust/parse/rust-cfg-parser.cc
../../gcc/rust/lex/rust-lex.cc: In member function ‘std::tuple<Rust::Codepoint, int, bool> Rust::Lexer::parse_utf8_escape(char)’:
../../gcc/rust/lex/rust-lex.cc:1326:32: error: unused parameter ‘opening_char’ [-Werror=unused-parameter]
 1326 | Lexer::parse_utf8_escape (char opening_char)
      |                           ~~~~~^~~~~~~~~~~~

[philberty]

Not sure why this is happening on the bootstrap build right now

[CohenArthur]

@philberty this PR fixes the issue. This is due to us changing the Makefile for the upstream patches

[CohenArthur]

Actually, this only exposed the underlying issue :) #1635 fixes the issue. It just needs to be reviewed