Switch musl build to v68

In practice there's little difference between the compiler-emitted
code for v68 vs v65.

But since eld lacks official support for architectures older than v68, these
linker warnings below are potentially concerning/confusing for users.

We'll switch to v68 for this build to match the default used by the compiler
and assembler.

    $ ./clang+llvm-20.1.2-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/bin/hexagon-unknown-linux-musl-clang -o foo foo.c -static -fuse-ld=eld
    Note: can not open search directory `/local/mnt/workspace/upstream/toolchain_for_hexagon/clang+llvm-20.1.2-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/bin/../target/hexagon/lib/v68'
    Warning: Support for ISA hexagonv65 is deprecated for input file /local/mnt/workspace/upstream/toolchain_for_hexagon/clang+llvm-20.1.2-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/bin/../target/hexagon-unknown-linux-musl//usr/lib/crt1.o
    Warning: Support for ISA hexagonv65 is deprecated for input file /local/mnt/workspace/upstream/toolchain_for_hexagon/clang+llvm-20.1.2-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/bin/../target/hexagon-unknown-linux-musl//usr/lib/libc.a(__libc_start_main.lo)
    Warning: Support for ISA hexagonv65 is deprecated for input file /local/mnt/workspace/upstream/toolchain_for_hexagon/clang+llvm-20.1.2-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/bin/../target/hexagon-unknown-linux-musl//usr/lib/libc.a(exit.lo)
    Warning: Support for ISA hexagonv65 is deprecated for input file /local/mnt/workspace/upstream/toolchain_for_hexagon/clang+llvm-20.1.2-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/bin/../target/hexagon-unknown-linux-musl//usr/lib/libc.a(defsysinfo.lo)
    Warning: Support for ISA hexagonv65 is deprecated for input file /local/mnt/workspace/upstream/toolchain_for_hexagon/clang+llvm-20.1.2-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/bin/../target/hexagon-unknown-linux-musl//usr/lib/libc.a(libc.lo)
    Warning: Support for ISA hexagonv65 is deprecated for input file /local/mnt/workspace/upstream/toolchain_for_hexagon/clang+llvm-20.1.2-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/bin/../target/hexagon-unknown-linux-musl//usr/lib/libc.a(memset.lo)
    Warning: Support for ISA hexagonv65 is deprecated for input file /local/mnt/workspace/upstream/toolchain_for_hexagon/clang+llvm-20.1.2-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/bin/../target/hexagon-unknown-linux-musl//usr/lib/libc.a(__environ.lo)
    Warning: Support for ISA hexagonv65 is deprecated for input file /local/mnt/workspace/upstream/toolchain_for_hexagon/clang+llvm-20.1.2-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/bin/../target/hexagon-unknown-linux-musl//usr/lib/libc.a(__init_tls.lo)
    Warning: Support for ISA hexagonv65 is deprecated for input file /local/mnt/workspace/upstream/toolchain_for_hexagon/clang+llvm-20.1.2-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/bin/../target/hexagon-unknown-linux-musl//usr/lib/libc.a(_Exit.lo)
    Warning: Too many warnings emitted (use --warn-limit=0 to see all warnings)

Signed-off-by: Brian Cain <[email protected]>

Author: androm3da

build-toolchain.sh

@@ -163,7 +163,7 @@ build_musl_headers() {
 	CC=${TOOLCHAIN_INSTALL}/x86_64-linux-gnu/bin/hexagon-unknown-linux-musl-clang \
 		CROSS_COMPILE=hexagon-unknown-linux-musl \
 		LIBCC=${HEX_TOOLS_TARGET_BASE}/lib/libclang_rt.builtins-hexagon.a \
-		CROSS_CFLAGS="-G0 -O0 -mv65 -fno-builtin --target=hexagon-unknown-linux-musl" \
+		CROSS_CFLAGS="-G0 -O0 -mv68 -fno-builtin --target=hexagon-unknown-linux-musl" \
 		./configure --target=hexagon --prefix=${HEX_TOOLS_TARGET_BASE}
 	PATH=${TOOLCHAIN_INSTALL}/x86_64-linux-gnu/bin/:$PATH make install-headers
 
@@ -307,7 +307,7 @@ fi
 ccache --show-stats
 
 
-MUSL_CFLAGS="-G0 -O0 -mv65 -fno-builtin -mlong-calls --target=hexagon-unknown-linux-musl"
+MUSL_CFLAGS="-G0 -O0 -mv68 -fno-builtin -mlong-calls --target=hexagon-unknown-linux-musl"
 
 # Workaround, 'C()' macro results in switch over bool:
 MUSL_CFLAGS="${MUSL_CFLAGS} -Wno-switch-bool"