Description of problem:
Package swift-lang fails to build from source in Fedora Rawhide/37 with following error:

FAILED: src/CMakeFiles/dispatch.dir/shims/yield.c.o 
/usr/bin/clang -DDISPATCH_USE_DTRACE=0 -DHAVE_CONFIG_H -D_GNU_SOURCE=1 -I. -I/builddir/build/BUILD/swift-source/swift-corelibs-libdispatch -I/builddir/build/BUILD/swift-source/swift-corelibs-libdispatch/src -Isrc -I/builddir/build/BUILD/swift-source/swift-corelibs-libdispatch/private -I/builddir/build/BUILD/swift-source/swift-corelibs-libdispatch/src/BlocksRuntime -Wno-unknown-warning-option -Werror=unguarded-availability-new -fno-stack-protector -fPIC -fno-semantic-interposition -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wdelete-non-virtual-dtor -Wstring-conversion -Wmisleading-indentation -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -fPIC -fvisibility=hidden -Werror -Wall -Wextra -Warray-bounds-pointer-arithmetic -Wassign-enum -Watomic-properties -Wcomma -Wconditional-uninitialized -Wconversion -Wcovered-switch-default -Wdate-time -Wdeprecated -Wdocumentation -Wdouble-promotion -Wduplicate-enum -Wexpansion-to-defined -Wfloat-equal -Widiomatic-parentheses -Winfinite-recursion -Wmissing-prototypes -Wnewline-eof -Wnullable-to-nonnull-conversion -Wobjc-interface-ivars -Wover-aligned -Wpacked -Wpointer-arith -Wselector -Wshadow -Wshorten-64-to-32 -Wsign-conversion -Wstatic-in-inline -Wsuper-class-method-mismatch -Wswitch -Wunguarded-availability -Wunreachable-code -Wunused -Wno-unknown-warning-option -Wno-trigraphs -Wno-four-char-constants -Wno-disabled-macro-expansion -Wno-pedantic -Wno-bad-function-cast -Wno-c++-compat -Wno-c++98-compat -Wno-c++98-compat-pedantic -Wno-cast-align -Wno-cast-qual -Wno-documentation-unknown-command -Wno-format-nonliteral -Wno-missing-variable-declarations -Wno-old-style-cast -Wno-padded -Wno-reserved-id-macro -Wno-shift-sign-overflow -Wno-undef -Wno-unreachable-code-aggressive -Wno-unused-macros -Wno-used-but-marked-unused -Wno-void-pointer-to-int-cast -Wno-vla -Wno-error=assign-enum -fno-exceptions -fblocks -momit-leaf-frame-pointer -std=gnu11 -MD -MT src/CMakeFiles/dispatch.dir/shims/yield.c.o -MF src/CMakeFiles/dispatch.dir/shims/yield.c.o.d -o src/CMakeFiles/dispatch.dir/shims/yield.c.o -c /builddir/build/BUILD/swift-source/swift-corelibs-libdispatch/src/shims/yield.c
/builddir/build/BUILD/swift-source/swift-corelibs-libdispatch/src/shims/yield.c:27:6: error: variable 'spins' set but not used [-Werror,-Wunused-but-set-variable]
        int spins = 0;
            ^
1 error generated.

Version-Release number of selected component (if applicable):
5.7-1.fc38

Steps to Reproduce:
koji build --scratch f38 swift-lang-5.6.3-1.fc38.src.rpm

Additional info:
This package is tracked by Koschei. See:
https://koschei.fedoraproject.org/package/swift-lang

Dependency changes from the latest successful build:
https://koschei.fedoraproject.org/build/13702045