Fix clang: error: unsupported argument 'native' to option '-march=' Error on ARM macOS

[sshaw]

~/code/ruby/smarter_csv >sw_vers
ProductName:		macOS
ProductVersion:		15.5
BuildVersion:		24F74

~/code/ruby/smarter_csv >uname -a
Darwin Mac.fios-router.home 24.5.0 Darwin Kernel Version 24.5.0: Tue Apr 22 19:54:29 PDT 2025; root:xnu-11417.121.6~2/RELEASE_ARM64_T6030 arm64

bundle installin' results in:

Installing smarter_csv 1.14.4 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    current directory: /Users/sshaw/.asdf/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/smarter_csv-1.14.4/ext/smarter_csv
/Users/sshaw/.asdf/installs/ruby/3.3.5/bin/ruby extconf.rb
creating Makefile

current directory: /Users/sshaw/.asdf/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/smarter_csv-1.14.4/ext/smarter_csv
make DESTDIR\= sitearchdir\=./.gem.20260110-99544-wg9eqp sitelibdir\=./.gem.20260110-99544-wg9eqp clean

current directory: /Users/sshaw/.asdf/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/smarter_csv-1.14.4/ext/smarter_csv
make DESTDIR\= sitearchdir\=./.gem.20260110-99544-wg9eqp sitelibdir\=./.gem.20260110-99544-wg9eqp
compiling smarter_csv.c
clang: error: unsupported argument 'native' to option '-march='
make: *** [smarter_csv.o] Error 1

make failed, exit code 2
....

I certainly could be using a relatively older clang. These are the only CPU-related options this version supports:

~/code/ruby/smarter_csv >clang --print-supported-cpus
Apple clang version 16.0.0 (clang-1600.0.26.3)
Target: arm64-apple-darwin24.5.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
Available CPUs for this target:

	a64fx
	ampere1
	ampere1a
	apple-a10
	apple-a11
	apple-a12
	apple-a13
	apple-a14
	apple-a15
	apple-a16
	apple-a7
	apple-a8
	apple-a9
	apple-latest
	apple-m1
	apple-m2
	apple-s4
	apple-s5
	carmel
	cortex-a34
	cortex-a35
	cortex-a510
	cortex-a53
	cortex-a55
	cortex-a57
	cortex-a65
	cortex-a65ae
	cortex-a710
	cortex-a715
	cortex-a72
	cortex-a73
	cortex-a75
	cortex-a76
	cortex-a76ae
	cortex-a77
	cortex-a78
	cortex-a78c
	cortex-r82
	cortex-x1
	cortex-x1c
	cortex-x2
	cortex-x3
	cyclone
	exynos-m3
	exynos-m4
	exynos-m5
	falkor
	generic
	kryo
	neoverse-512tvb
	neoverse-e1
	neoverse-n1
	neoverse-n2
	neoverse-v1
	neoverse-v2
	saphira
	thunderx
	thunderx2t99
	thunderx3t110
	thunderxt81
	thunderxt83
	thunderxt88
	tsv110

Nevertheless, I made an update to extconf.rb that works with this clang + platform.

For posterity was able to workaround this using bundle config:

bundle config build.smarter_csv --with-cflags="-O3 -flto -fomit-frame-pointer -DNDEBUG"