testsuite: Rename c2x-*, gnu2x-* tests to c23-*, gnu23-*

testsuite: Rename c2x-*, gnu2x-* tests to c23-*, gnu23-*

Completing the move to refer to C23 in place of C2X, rename all tests
with "c2x" or "gnu2x" in their names to use "c23" or "gnu23" instead.
17 files in the testsuite that referred to such tests (or, in one
case, a generated .i file to be scanned) by those names are updated
for the renaming.

Bootstrapped with no regressions for x86_64-pc-linux-gnu.

gcc/testsuite/
	* gcc.dg/atomic/c2x-stdatomic-lockfree-char8_t.c: Move to ...
	* gcc.dg/atomic/c23-stdatomic-lockfree-char8_t.c: ... here.
	* gcc.dg/atomic/c2x-stdatomic-var-init-1.c: Move to ...
	* gcc.dg/atomic/c23-stdatomic-var-init-1.c: ... here.
	* gcc.dg/atomic/gnu2x-stdatomic-lockfree-char8_t.c: Move to ...
	* gcc.dg/atomic/gnu23-stdatomic-lockfree-char8_t.c: ... here.
	Update reference to moved file.
	* gcc.dg/c2x-align-1.c: Move to ...
	* gcc.dg/c23-align-1.c: ... here.
	* gcc.dg/c2x-align-6.c: Move to ...
	* gcc.dg/c23-align-6.c: ... here.
	* gcc.dg/c2x-attr-deprecated-1.c: Move to ...
	* gcc.dg/c23-attr-deprecated-1.c: ... here.  Update reference to
	moved file.
	* gcc.dg/c2x-attr-deprecated-2.c: Move to ...
	* gcc.dg/c23-attr-deprecated-2.c: ... here.
	* gcc.dg/c2x-attr-deprecated-3.c: Move to ...
	* gcc.dg/c23-attr-deprecated-3.c: ... here.
	* gcc.dg/c2x-attr-deprecated-4.c: Move to ...
	* gcc.dg/c23-attr-deprecated-4.c: ... here.
	* gcc.dg/c2x-attr-fallthrough-1.c: Move to ...
	* gcc.dg/c23-attr-fallthrough-1.c: ... here.
	* gcc.dg/c2x-attr-fallthrough-2.c: Move to ...
	* gcc.dg/c23-attr-fallthrough-2.c: ... here.
	* gcc.dg/c2x-attr-fallthrough-3.c: Move to ...
	* gcc.dg/c23-attr-fallthrough-3.c: ... here.
	* gcc.dg/c2x-attr-fallthrough-4.c: Move to ...
	* gcc.dg/c23-attr-fallthrough-4.c: ... here.
	* gcc.dg/c2x-attr-fallthrough-5.c: Move to ...
	* gcc.dg/c23-attr-fallthrough-5.c: ... here.
	* gcc.dg/c2x-attr-fallthrough-6.c: Move to ...
	* gcc.dg/c23-attr-fallthrough-6.c: ... here.
	* gcc.dg/c2x-attr-maybe_unused-1.c: Move to ...
	* gcc.dg/c23-attr-maybe_unused-1.c: ... here.
	* gcc.dg/c2x-attr-maybe_unused-2.c: Move to ...
	* gcc.dg/c23-attr-maybe_unused-2.c: ... here.
	* gcc.dg/c2x-attr-maybe_unused-3.c: Move to ...
	* gcc.dg/c23-attr-maybe_unused-3.c: ... here.
	* gcc.dg/c2x-attr-maybe_unused-4.c: Move to ...
	* gcc.dg/c23-attr-maybe_unused-4.c: ... here.
	* gcc.dg/c2x-attr-nodiscard-1.c: Move to ...
	* gcc.dg/c23-attr-nodiscard-1.c: ... here.
	* gcc.dg/c2x-attr-nodiscard-2.c: Move to ...
	* gcc.dg/c23-attr-nodiscard-2.c: ... here.
	* gcc.dg/c2x-attr-nodiscard-3.c: Move to ...
	* gcc.dg/c23-attr-nodiscard-3.c: ... here.
	* gcc.dg/c2x-attr-nodiscard-4.c: Move to ...
	* gcc.dg/c23-attr-nodiscard-4.c: ... here.
	* gcc.dg/c2x-attr-noreturn-1.c: Move to ...
	* gcc.dg/c23-attr-noreturn-1.c: ... here.
	* gcc.dg/c2x-attr-noreturn-2.c: Move to ...
	* gcc.dg/c23-attr-noreturn-2.c: ... here.
	* gcc.dg/c2x-attr-noreturn-3.c: Move to ...
	* gcc.dg/c23-attr-noreturn-3.c: ... here.
	* gcc.dg/c2x-attr-syntax-1.c: Move to ...
	* gcc.dg/c23-attr-syntax-1.c: ... here.
	* gcc.dg/c2x-attr-syntax-2.c: Move to ...
	* gcc.dg/c23-attr-syntax-2.c: ... here.
	* gcc.dg/c2x-attr-syntax-3.c: Move to ...
	* gcc.dg/c23-attr-syntax-3.c: ... here.
	* gcc.dg/c2x-attr-syntax-4.c: Move to ...
	* gcc.dg/c23-attr-syntax-4.c: ... here.
	* gcc.dg/c2x-attr-syntax-5.c: Move to ...
	* gcc.dg/c23-attr-syntax-5.c: ... here.
	* gcc.dg/c2x-attr-syntax-6.c: Move to ...
	* gcc.dg/c23-attr-syntax-6.c: ... here.
	* gcc.dg/c2x-attr-syntax-7.c: Move to ...
	* gcc.dg/c23-attr-syntax-7.c: ... here.
	* gcc.dg/c2x-auto-1.c: Move to ...
	* gcc.dg/c23-auto-1.c: ... here.
	* gcc.dg/c2x-auto-2.c: Move to ...
	* gcc.dg/c23-auto-2.c: ... here.
	* gcc.dg/c2x-auto-3.c: Move to ...
	* gcc.dg/c23-auto-3.c: ... here.
	* gcc.dg/c2x-auto-4.c: Move to ...
	* gcc.dg/c23-auto-4.c: ... here.
	* gcc.dg/c2x-binary-constants-1.c: Move to ...
	* gcc.dg/c23-binary-constants-1.c: ... here.
	* gcc.dg/c2x-binary-constants-2.c: Move to ...
	* gcc.dg/c23-binary-constants-2.c: ... here.
	* gcc.dg/c2x-binary-constants-3.c: Move to ...
	* gcc.dg/c23-binary-constants-3.c: ... here.
	* gcc.dg/c2x-bool-1.c: Move to ...
	* gcc.dg/c23-bool-1.c: ... here.
	* gcc.dg/c2x-bool-2.c: Move to ...
	* gcc.dg/c23-bool-2.c: ... here.
	* gcc.dg/c2x-bool-limits-1.c: Move to ...
	* gcc.dg/c23-bool-limits-1.c: ... here.
	* gcc.dg/c2x-builtins-1.c: Move to ...
	* gcc.dg/c23-builtins-1.c: ... here.
	* gcc.dg/c2x-complit-1.c: Move to ...
	* gcc.dg/c23-complit-1.c: ... here.
	* gcc.dg/c2x-complit-2.c: Move to ...
	* gcc.dg/c23-complit-2.c: ... here.
	* gcc.dg/c2x-complit-3.c: Move to ...
	* gcc.dg/c23-complit-3.c: ... here.
	* gcc.dg/c2x-complit-4.c: Move to ...
	* gcc.dg/c23-complit-4.c: ... here.
	* gcc.dg/c2x-complit-5.c: Move to ...
	* gcc.dg/c23-complit-5.c: ... here.
	* gcc.dg/c2x-complit-6.c: Move to ...
	* gcc.dg/c23-complit-6.c: ... here.
	* gcc.dg/c2x-complit-7.c: Move to ...
	* gcc.dg/c23-complit-7.c: ... here.
	* gcc.dg/c2x-complit-8.c: Move to ...
	* gcc.dg/c23-complit-8.c: ... here.
	* gcc.dg/c2x-concat-1.c: Move to ...
	* gcc.dg/c23-concat-1.c: ... here.
	* gcc.dg/c2x-constexpr-1.c: Move to ...
	* gcc.dg/c23-constexpr-1.c: ... here.
	* gcc.dg/c2x-constexpr-2a.c: Move to ...
	* gcc.dg/c23-constexpr-2a.c: ... here.  Update reference to moved
	file.
	* gcc.dg/c2x-constexpr-2b.c: Move to ...
	* gcc.dg/c23-constexpr-2b.c: ... here.
	* gcc.dg/c2x-constexpr-3.c: Move to ...
	* gcc.dg/c23-constexpr-3.c: ... here.
	* gcc.dg/c2x-constexpr-4.c: Move to ...
	* gcc.dg/c23-constexpr-4.c: ... here.
	* gcc.dg/c2x-constexpr-5.c: Move to ...
	* gcc.dg/c23-constexpr-5.c: ... here.
	* gcc.dg/c2x-constexpr-6.c: Move to ...
	* gcc.dg/c23-constexpr-6.c: ... here.
	* gcc.dg/c2x-constexpr-7.c: Move to ...
	* gcc.dg/c23-constexpr-7.c: ... here.
	* gcc.dg/c2x-constexpr-8.c: Move to ...
	* gcc.dg/c23-constexpr-8.c: ... here.
	* gcc.dg/c2x-constexpr-9.c: Move to ...
	* gcc.dg/c23-constexpr-9.c: ... here.
	* gcc.dg/c2x-digit-separators-1.c: Move to ...
	* gcc.dg/c23-digit-separators-1.c: ... here.
	* gcc.dg/c2x-digit-separators-2.c: Move to ...
	* gcc.dg/c23-digit-separators-2.c: ... here.
	* gcc.dg/c2x-digit-separators-3.c: Move to ...
	* gcc.dg/c23-digit-separators-3.c: ... here.
	* gcc.dg/c2x-empty-init-1.c: Move to ...
	* gcc.dg/c23-empty-init-1.c: ... here.
	* gcc.dg/c2x-empty-init-2.c: Move to ...
	* gcc.dg/c23-empty-init-2.c: ... here.
	* gcc.dg/c2x-empty-init-3.c: Move to ...
	* gcc.dg/c23-empty-init-3.c: ... here.
	* gcc.dg/c2x-enum-1.c: Move to ...
	* gcc.dg/c23-enum-1.c: ... here.
	* gcc.dg/c2x-enum-2.c: Move to ...
	* gcc.dg/c23-enum-2.c: ... here.
	* gcc.dg/c2x-enum-3.c: Move to ...
	* gcc.dg/c23-enum-3.c: ... here.
	* gcc.dg/c2x-enum-4.c: Move to ...
	* gcc.dg/c23-enum-4.c: ... here.
	* gcc.dg/c2x-enum-5.c: Move to ...
	* gcc.dg/c23-enum-5.c: ... here.
	* gcc.dg/c2x-enum-6.c: Move to ...
	* gcc.dg/c23-enum-6.c: ... here.
	* gcc.dg/c2x-enum-7.c: Move to ...
	* gcc.dg/c23-enum-7.c: ... here.
	* gcc.dg/c2x-enum-8.c: Move to ...
	* gcc.dg/c23-enum-8.c: ... here.
	* gcc.dg/c2x-float-1.c: Move to ...
	* gcc.dg/c23-float-1.c: ... here.
	* gcc.dg/c2x-float-10.c: Move to ...
	* gcc.dg/c23-float-10.c: ... here.
	* gcc.dg/c2x-float-11.c: Move to ...
	* gcc.dg/c23-float-11.c: ... here.
	* gcc.dg/c2x-float-12.c: Move to ...
	* gcc.dg/c23-float-12.c: ... here.
	* gcc.dg/c2x-float-13.c: Move to ...
	* gcc.dg/c23-float-13.c: ... here.
	* gcc.dg/c2x-float-2.c: Move to ...
	* gcc.dg/c23-float-2.c: ... here.
	* gcc.dg/c2x-float-3.c: Move to ...
	* gcc.dg/c23-float-3.c: ... here.
	* gcc.dg/c2x-float-4.c: Move to ...
	* gcc.dg/c23-float-4.c: ... here.
	* gcc.dg/c2x-float-5.c: Move to ...
	* gcc.dg/c23-float-5.c: ... here.
	* gcc.dg/c2x-float-6.c: Move to ...
	* gcc.dg/c23-float-6.c: ... here.
	* gcc.dg/c2x-float-7a.c: Move to ...
	* gcc.dg/c23-float-7a.c: ... here.
	* gcc.dg/c2x-float-7b.c: Move to ...
	* gcc.dg/c23-float-7b.c: ... here.
	* gcc.dg/c2x-float-7c.c: Move to ...
	* gcc.dg/c23-float-7c.c: ... here.
	* gcc.dg/c2x-float-8.c: Move to ...
	* gcc.dg/c23-float-8.c: ... here.
	* gcc.dg/c2x-float-9.c: Move to ...
	* gcc.dg/c23-float-9.c: ... here.
	* gcc.dg/c2x-float-no-dfp-1.c: Move to ...
	* gcc.dg/c23-float-no-dfp-1.c: ... here.
	* gcc.dg/c2x-float-no-dfp-2.c: Move to ...
	* gcc.dg/c23-float-no-dfp-2.c: ... here.  Update reference to
	moved file.
	* gcc.dg/c2x-float-no-dfp-3.c: Move to ...
	* gcc.dg/c23-float-no-dfp-3.c: ... here.
	* gcc.dg/c2x-float-no-dfp-4.c: Move to ...
	* gcc.dg/c23-float-no-dfp-4.c: ... here.  Update reference to
	moved file.
	* gcc.dg/c2x-floatn-1.c: Move to ...
	* gcc.dg/c23-floatn-1.c: ... here.
	* gcc.dg/c2x-floatn-2.c: Move to ...
	* gcc.dg/c23-floatn-2.c: ... here.
	* gcc.dg/c2x-floatn-3.c: Move to ...
	* gcc.dg/c23-floatn-3.c: ... here.
	* gcc.dg/c2x-floatn-4.c: Move to ...
	* gcc.dg/c23-floatn-4.c: ... here.
	* gcc.dg/c2x-floatn-5.c: Move to ...
	* gcc.dg/c23-floatn-5.c: ... here.
	* gcc.dg/c2x-floatn-6.c: Move to ...
	* gcc.dg/c23-floatn-6.c: ... here.
	* gcc.dg/c2x-floatn-7.c: Move to ...
	* gcc.dg/c23-floatn-7.c: ... here.
	* gcc.dg/c2x-floatn-8.c: Move to ...
	* gcc.dg/c23-floatn-8.c: ... here.
	* gcc.dg/c2x-fordecl-1.c: Move to ...
	* gcc.dg/c23-fordecl-1.c: ... here.
	* gcc.dg/c2x-fordecl-2.c: Move to ...
	* gcc.dg/c23-fordecl-2.c: ... here.
	* gcc.dg/c2x-fordecl-3.c: Move to ...
	* gcc.dg/c23-fordecl-3.c: ... here.
	* gcc.dg/c2x-fordecl-4.c: Move to ...
	* gcc.dg/c23-fordecl-4.c: ... here.
	* gcc.dg/c2x-has-c-attribute-1.c: Move to ...
	* gcc.dg/c23-has-c-attribute-1.c: ... here.
	* gcc.dg/c2x-has-c-attribute-2.c: Move to ...
	* gcc.dg/c23-has-c-attribute-2.c: ... here.
	* gcc.dg/c2x-has-c-attribute-3.c: Move to ...
	* gcc.dg/c23-has-c-attribute-3.c: ... here.
	* gcc.dg/c2x-has-c-attribute-4.c: Move to ...
	* gcc.dg/c23-has-c-attribute-4.c: ... here.
	* gcc.dg/c2x-labels-1.c: Move to ...
	* gcc.dg/c23-labels-1.c: ... here.
	* gcc.dg/c2x-labels-2.c: Move to ...
	* gcc.dg/c23-labels-2.c: ... here.
	* gcc.dg/c2x-labels-3.c: Move to ...
	* gcc.dg/c23-labels-3.c: ... here.
	* gcc.dg/c2x-limits-1.c: Move to ...
	* gcc.dg/c23-limits-1.c: ... here.
	* gcc.dg/c2x-no-dfp-1.c: Move to ...
	* gcc.dg/c23-no-dfp-1.c: ... here.
	* gcc.dg/c2x-nullptr-1.c: Move to ...
	* gcc.dg/c23-nullptr-1.c: ... here.
	* gcc.dg/c2x-nullptr-2.c: Move to ...
	* gcc.dg/c23-nullptr-2.c: ... here.
	* gcc.dg/c2x-nullptr-3.c: Move to ...
	* gcc.dg/c23-nullptr-3.c: ... here.
	* gcc.dg/c2x-nullptr-4.c: Move to ...
	* gcc.dg/c23-nullptr-4.c: ... here.
	* gcc.dg/c2x-nullptr-5.c: Move to ...
	* gcc.dg/c23-nullptr-5.c: ... here.
	* gcc.dg/c2x-nullptr-6.c: Move to ...
	* gcc.dg/c23-nullptr-6.c: ... here.
	* gcc.dg/c2x-old-style-definition-1.c: Move to ...
	* gcc.dg/c23-old-style-definition-1.c: ... here.
	* gcc.dg/c2x-old-style-definition-2.c: Move to ...
	* gcc.dg/c23-old-style-definition-2.c: ... here.
	* gcc.dg/c2x-old-style-definition-3.c: Move to ...
	* gcc.dg/c23-old-style-definition-3.c: ... here.
	* gcc.dg/c2x-old-style-definition-4.c: Move to ...
	* gcc.dg/c23-old-style-definition-4.c: ... here.
	* gcc.dg/c2x-old-style-definition-5.c: Move to ...
	* gcc.dg/c23-old-style-definition-5.c: ... here.
	* gcc.dg/c2x-old-style-definition-6.c: Move to ...
	* gcc.dg/c23-old-style-definition-6.c: ... here.
	* gcc.dg/c2x-parm-omit-1.c: Move to ...
	* gcc.dg/c23-parm-omit-1.c: ... here.
	* gcc.dg/c2x-parm-omit-2.c: Move to ...
	* gcc.dg/c23-parm-omit-2.c: ... here.
	* gcc.dg/c2x-parm-omit-3.c: Move to ...
	* gcc.dg/c23-parm-omit-3.c: ... here.
	* gcc.dg/c2x-parm-omit-4.c: Move to ...
	* gcc.dg/c23-parm-omit-4.c: ... here.
	* gcc.dg/c2x-qual-1.c: Move to ...
	* gcc.dg/c23-qual-1.c: ... here.
	* gcc.dg/c2x-qual-2.c: Move to ...
	* gcc.dg/c23-qual-2.c: ... here.
	* gcc.dg/c2x-qual-3.c: Move to ...
	* gcc.dg/c23-qual-3.c: ... here.
	* gcc.dg/c2x-qual-4.c: Move to ...
	* gcc.dg/c23-qual-4.c: ... here.
	* gcc.dg/c2x-qual-5.c: Move to ...
	* gcc.dg/c23-qual-5.c: ... here.
	* gcc.dg/c2x-qual-6.c: Move to ...
	* gcc.dg/c23-qual-6.c: ... here.
	* gcc.dg/c2x-qual-7.c: Move to ...
	* gcc.dg/c23-qual-7.c: ... here.
	* gcc.dg/c2x-static-assert-1.c: Move to ...
	* gcc.dg/c23-static-assert-1.c: ... here.
	* gcc.dg/c2x-static-assert-2.c: Move to ...
	* gcc.dg/c23-static-assert-2.c: ... here.
	* gcc.dg/c2x-static-assert-3.c: Move to ...
	* gcc.dg/c23-static-assert-3.c: ... here.
	* gcc.dg/c2x-static-assert-4.c: Move to ...
	* gcc.dg/c23-static-assert-4.c: ... here.
	* gcc.dg/c2x-stdarg-1.c: Move to ...
	* gcc.dg/c23-stdarg-1.c: ... here.
	* gcc.dg/c2x-stdarg-2.c: Move to ...
	* gcc.dg/c23-stdarg-2.c: ... here.
	* gcc.dg/c2x-stdarg-3.c: Move to ...
	* gcc.dg/c23-stdarg-3.c: ... here.
	* gcc.dg/c2x-stdarg-4.c: Move to ...
	* gcc.dg/c23-stdarg-4.c: ... here.
	* gcc.dg/c2x-stdarg-5.c: Move to ...
	* gcc.dg/c23-stdarg-5.c: ... here.
	* gcc.dg/c2x-stdatomic-1.c: Move to ...
	* gcc.dg/c23-stdatomic-1.c: ... here.
	* gcc.dg/c2x-stddef-1.c: Move to ...
	* gcc.dg/c23-stddef-1.c: ... here.
	* gcc.dg/c2x-stdint-1.c: Move to ...
	* gcc.dg/c23-stdint-1.c: ... here.
	* gcc.dg/c2x-thread-local-1.c: Move to ...
	* gcc.dg/c23-thread-local-1.c: ... here.
	* gcc.dg/c2x-thread-local-2.c: Move to ...
	* gcc.dg/c23-thread-local-2.c: ... here.
	* gcc.dg/c2x-typeof-1.c: Move to ...
	* gcc.dg/c23-typeof-1.c: ... here.
	* gcc.dg/c2x-typeof-2.c: Move to ...
	* gcc.dg/c23-typeof-2.c: ... here.
	* gcc.dg/c2x-typeof-3.c: Move to ...
	* gcc.dg/c23-typeof-3.c: ... here.
	* gcc.dg/c2x-unproto-1.c: Move to ...
	* gcc.dg/c23-unproto-1.c: ... here.
	* gcc.dg/c2x-unproto-2.c: Move to ...
	* gcc.dg/c23-unproto-2.c: ... here.
	* gcc.dg/c2x-unproto-3.c: Move to ...
	* gcc.dg/c23-unproto-3.c: ... here.
	* gcc.dg/c2x-unproto-4.c: Move to ...
	* gcc.dg/c23-unproto-4.c: ... here.
	* gcc.dg/c2x-unreachable-1.c: Move to ...
	* gcc.dg/c23-unreachable-1.c: ... here.
	* gcc.dg/c2x-utf8char-1.c: Move to ...
	* gcc.dg/c23-utf8char-1.c: ... here.
	* gcc.dg/c2x-utf8char-2.c: Move to ...
	* gcc.dg/c23-utf8char-2.c: ... here.
	* gcc.dg/c2x-utf8char-3.c: Move to ...
	* gcc.dg/c23-utf8char-3.c: ... here.
	* gcc.dg/c2x-utf8str-type.c: Move to ...
	* gcc.dg/c23-utf8str-type.c: ... here.
	* gcc.dg/c2x-utf8str.c: Move to ...
	* gcc.dg/c23-utf8str.c: ... here.
	* gcc.dg/cpp/c2x-elifdef-1.c: Move to ...
	* gcc.dg/cpp/c23-elifdef-1.c: ... here.
	* gcc.dg/cpp/c2x-elifdef-2.c: Move to ...
	* gcc.dg/cpp/c23-elifdef-2.c: ... here.
	* gcc.dg/cpp/c2x-scope-1.c: Move to ...
	* gcc.dg/cpp/c23-scope-1.c: ... here.
	* gcc.dg/cpp/c2x-scope-2.c: Move to ...
	* gcc.dg/cpp/c23-scope-2.c: ... here.  Update reference to moved
	file.
	* gcc.dg/cpp/c2x-trigraphs-1.c: Move to ...
	* gcc.dg/cpp/c23-trigraphs-1.c: ... here.
	* gcc.dg/cpp/c2x-trigraphs-2.c: Move to ...
	* gcc.dg/cpp/c23-trigraphs-2.c: ... here.
	* gcc.dg/cpp/c2x-ucn-1.c: Move to ...
	* gcc.dg/cpp/c23-ucn-1.c: ... here.
	* gcc.dg/cpp/c2x-ucnid-1-utf8.c: Move to ...
	* gcc.dg/cpp/c23-ucnid-1-utf8.c: ... here.
	* gcc.dg/cpp/c2x-ucnid-1.c: Move to ...
	* gcc.dg/cpp/c23-ucnid-1.c: ... here.
	* gcc.dg/cpp/c2x-va-opt-1.c: Move to ...
	* gcc.dg/cpp/c23-va-opt-1.c: ... here.
	* gcc.dg/cpp/c2x-warning-1.c: Move to ...
	* gcc.dg/cpp/c23-warning-1.c: ... here.
	* gcc.dg/cpp/c2x-warning-2.c: Move to ...
	* gcc.dg/cpp/c23-warning-2.c: ... here.
	* gcc.dg/cpp/gnu2x-warning-1.c: Move to ...
	* gcc.dg/cpp/gnu23-warning-1.c: ... here.
	* gcc.dg/cpp/gnu2x-warning-2.c: Move to ...
	* gcc.dg/cpp/gnu23-warning-2.c: ... here.
	* gcc.dg/dfp/c2x-builtins-dfp-1.c: Move to ...
	* gcc.dg/dfp/c23-builtins-dfp-1.c: ... here.
	* gcc.dg/dfp/c2x-constants-1.c: Move to ...
	* gcc.dg/dfp/c23-constants-1.c: ... here.
	* gcc.dg/dfp/c2x-constants-2.c: Move to ...
	* gcc.dg/dfp/c23-constants-2.c: ... here.
	* gcc.dg/dfp/c2x-constexpr-dfp-1.c: Move to ...
	* gcc.dg/dfp/c23-constexpr-dfp-1.c: ... here.
	* gcc.dg/dfp/c2x-constexpr-dfp-2.c: Move to ...
	* gcc.dg/dfp/c23-constexpr-dfp-2.c: ... here.
	* gcc.dg/dfp/c2x-float-dfp-1.c: Move to ...
	* gcc.dg/dfp/c23-float-dfp-1.c: ... here.
	* gcc.dg/dfp/c2x-float-dfp-2.c: Move to ...
	* gcc.dg/dfp/c23-float-dfp-2.c: ... here.  Update reference to
	moved file.
	* gcc.dg/dfp/c2x-float-dfp-3.c: Move to ...
	* gcc.dg/dfp/c23-float-dfp-3.c: ... here.
	* gcc.dg/dfp/c2x-float-dfp-4.c: Move to ...
	* gcc.dg/dfp/c23-float-dfp-4.c: ... here.
	* gcc.dg/dfp/c2x-float-dfp-5.c: Move to ...
	* gcc.dg/dfp/c23-float-dfp-5.c: ... here.
	* gcc.dg/dfp/c2x-float-dfp-6.c: Move to ...
	* gcc.dg/dfp/c23-float-dfp-6.c: ... here.
	* gcc.dg/dfp/c2x-float-dfp-7.c: Move to ...
	* gcc.dg/dfp/c23-float-dfp-7.c: ... here.
	* gcc.dg/dfp/c2x-float-dfp-8.c: Move to ...
	* gcc.dg/dfp/c23-float-dfp-8.c: ... here.
	* gcc.dg/dfp/c2x-keywords-1.c: Move to ...
	* gcc.dg/dfp/c23-keywords-1.c: ... here.
	* gcc.dg/dfp/c2x-keywords-2.c: Move to ...
	* gcc.dg/dfp/c23-keywords-2.c: ... here.
	* gcc.dg/format/c2x-dfp-printf-1.c: Move to ...
	* gcc.dg/format/c23-dfp-printf-1.c: ... here.
	* gcc.dg/format/c2x-dfp-scanf-1.c: Move to ...
	* gcc.dg/format/c23-dfp-scanf-1.c: ... here.
	* gcc.dg/format/c2x-printf-1.c: Move to ...
	* gcc.dg/format/c23-printf-1.c: ... here.
	* gcc.dg/format/c2x-scanf-1.c: Move to ...
	* gcc.dg/format/c23-scanf-1.c: ... here.
	* gcc.dg/format/c2x-strftime-1.c: Move to ...
	* gcc.dg/format/c23-strftime-1.c: ... here.
	* gcc.dg/gnu2x-attr-syntax-1.c: Move to ...
	* gcc.dg/gnu23-attr-syntax-1.c: ... here.
	* gcc.dg/gnu2x-attr-syntax-2.c: Move to ...
	* gcc.dg/gnu23-attr-syntax-2.c: ... here.
	* gcc.dg/gnu2x-attrs-1.c: Move to ...
	* gcc.dg/gnu23-attrs-1.c: ... here.
	* gcc.dg/gnu2x-attrs-2.c: Move to ...
	* gcc.dg/gnu23-attrs-2.c: ... here.
	* gcc.dg/gnu2x-auto-1.c: Move to ...
	* gcc.dg/gnu23-auto-1.c: ... here.
	* gcc.dg/gnu2x-builtins-no-dfp-1.c: Move to ...
	* gcc.dg/gnu23-builtins-no-dfp-1.c: ... here.
	* gcc.dg/gnu2x-complit-1.c: Move to ...
	* gcc.dg/gnu23-complit-1.c: ... here.
	* gcc.dg/gnu2x-complit-2.c: Move to ...
	* gcc.dg/gnu23-complit-2.c: ... here.
	* gcc.dg/gnu2x-constexpr-1.c: Move to ...
	* gcc.dg/gnu23-constexpr-1.c: ... here.
	* gcc.dg/gnu2x-empty-init-1.c: Move to ...
	* gcc.dg/gnu23-empty-init-1.c: ... here.
	* gcc.dg/gnu2x-empty-init-2.c: Move to ...
	* gcc.dg/gnu23-empty-init-2.c: ... here.
	* gcc.dg/gnu2x-enum-1.c: Move to ...
	* gcc.dg/gnu23-enum-1.c: ... here.
	* gcc.dg/gnu2x-static-assert-1.c: Move to ...
	* gcc.dg/gnu23-static-assert-1.c: ... here.
	* gcc.dg/gnu2x-stdarg-1.c: Move to ...
	* gcc.dg/gnu23-stdarg-1.c: ... here.
	* gcc.dg/gnu2x-typeof-1.c: Move to ...
	* gcc.dg/gnu23-typeof-1.c: ... here.
	* gcc.dg/gnu2x-utf8char-1.c: Move to ...
	* gcc.dg/gnu23-utf8char-1.c: ... here.  Update reference to moved
	file.
	* gcc.dg/gnu2x-utf8str-type.c: Move to ...
	* gcc.dg/gnu23-utf8str-type.c: ... here.  Update reference to
	moved file.
	* gcc.dg/gnu2x-utf8str.c: Move to ...
	* gcc.dg/gnu23-utf8str.c: ... here.
	* gcc.dg/torture/builtin-fp-int-inexact-c2x.c: Move to ...
	* gcc.dg/torture/builtin-fp-int-inexact-c23.c: ... here.
	* gcc.dg/torture/c2x-stdarg-split-1a.c: Move to ...
	* gcc.dg/torture/c23-stdarg-split-1a.c: ... here.  Update
	reference to moved file.
	* gcc.dg/torture/c2x-stdarg-split-1b.c: Move to ...
	* gcc.dg/torture/c23-stdarg-split-1b.c: ... here.
	* objc.dg/attributes/gnu2x-attr-syntax-1.m: Move to ...
	* objc.dg/attributes/gnu23-attr-syntax-1.m: ... here.  Update
	reference to moved file.
	* g++.dg/cpp/elifdef-2.C: Update reference to moved file.
	* g++.dg/cpp/elifdef-4.C: Likewise.
	* gcc.dg/c11-float-dfp-1.c: Likewise.
	* gcc.dg/c11-float-dfp-2.c: Likewise.
	* gcc.dg/cpp/gnu11-elifdef-1.c: Likewise.
	* gcc.dg/dfp/ts18661-2-float-dfp-1.c: Likewise.