feat(cpu_features): add LLAR formula

[MeteorsLiu]

Closes #36

Translate the Conan Center cpu_features recipe (ffe30df101afd4dc95aac2f14b25bf345e64d7be) into an LLAR Formula for google/cpu_features.

Formula

• Module: google/cpu_features
• fromVer: v0.9.0 (Conan recipe covers 0.9.0 / 0.10.1; CMake install layout, public headers under include/cpu_features, and consumer contract match)
• Options: shared (default OFF), fPIC (default ON)
• CMake: BUILD_TESTING=OFF, CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS=ON, CMAKE_INSTALL_LIBDIR=lib, BUILD_SHARED_LIBS / CMAKE_POSITION_INDEPENDENT_CODE from options
• LICENSE copied to licenses/

pkg-config

Upstream does not install a .pc file. The Formula writes relocatable lib/pkgconfig/cpu_features.pc:

• prefix=${pcfiledir}/../..
• Cflags: -I${includedir}/cpu_features so the Conan test can #include <cpu_features_macros.h>
• Libs: -L${libdir} -lcpu_features plus -ldl on Linux/FreeBSD (Conan system_libs = ["dl"]; placed in Libs so default static pkgconfig.lookup is enough)
• metadata is the complete pkg-config --cflags --libs lookup
• onTest compiles the Conan test_package.c consumer with a flags file from that lookup

Apple CMAKE_SYSTEM_PROCESSOR=aarch64 is not set: v0.9.0+ already matches Darwin's arm64, and CI is linux/darwin only. Android ndk_compat is not exposed.

[fennoai]

Review summary

This adds a new LLAR build formula for google/cpu_features v0.9.0. It closely and correctly follows the established repo conventions (e.g. fast-pack/streamvbyte, intel/libipt): the filter/defaults blocks, CMake option handling, license copy, relocatable pkgconfig generation, defensive version panic, and shared-build LD_LIBRARY_PATH/DYLD_LIBRARY_PATH handling all match existing patterns. versions.json is minimal and correct.

One correctness bug worth fixing before merge (the PPC test include typo). A couple of minor, non-blocking notes are inline.

[fennoai]

[P1] PPC include header has a typo (ccpuinfo_ppc.h)

The PPC branch of the embedded test consumer includes <ccpuinfo_ppc.h> (leading double c). The upstream cpu_features header is cpuinfo_ppc.h. On a PPC target, onTest compiles this consumer and the include will fail with a file-not-found error, breaking the test. The other arch branches (cpuinfo_x86.h, cpuinfo_arm.h, cpuinfo_aarch64.h, cpuinfo_mips.h) are correct.

Suggested change

	#include <ccpuinfo_ppc.h>
	#include <cpuinfo_ppc.h>

[fennoai]

[P3] Version parse is whitespace-brittle for future tags

Version extraction relies on the exact literal prefix project(CpuFeatures VERSION plus .split(" ")[0]. This is correct for v0.9.0 (project(CpuFeatures VERSION 0.9.0 LANGUAGES C)). But since fromVer "v0.9.0" means this formula may be reused for later tags, any whitespace variation (extra space, tab, or a line-wrapped project(...)) would miss the prefix and hit the panic. Consider a whitespace-tolerant parse (e.g. tokenizing) as done in intel/libipt. Non-blocking.