[libc] Fix benchmarks CMakeLists.txt

[gchatelet]

Summary

This is a follow up on https://reviews.llvm.org/rGaba80d0734d1#886881.
target_link_options requires CMake>=3.13.

[MaskRay]

is too recent for current CMake version

Explicitly mention that target_link_options requires CMake>=3.13

[abrachet]

+1 to @MaskRay's suggestion to put it in the description so we can look at the FIXME's blame later.

[gchatelet]

• address comments

[gchatelet]

Sorry I messed up the Patches, I'll revert to previous state...

[gchatelet]

• revert

[gchatelet]

• updated commit message

libc/utils/benchmarks/CMakeLists.txt

 # libc-benchmark
 add_library(libc-benchmark
     STATIC
     EXCLUDE_FROM_ALL
     LibcBenchmark.cpp
     LibcBenchmark.h
 )
 add_dependencies(libc-benchmark google-benchmark)
-target_include_directories(libc-benchmark PUBLIC "${GOOGLE_BENCHMARK_LIBC_INSTALL}/include")
-target_link_options(libc-benchmark PUBLIC "${GOOGLE_BENCHMARK_LINK_FLAGS}")
-target_link_libraries(libc-benchmark PUBLIC LLVMSupport -lbenchmark Threads::Threads)
+target_include_directories(libc-benchmark
+    PUBLIC
+    "${GOOGLE_BENCHMARK_LIBC_INSTALL}/include"
+)
+target_link_libraries(libc-benchmark
+    PUBLIC
+    "${GOOGLE_BENCHMARK_LINK_FLAGS}" # FIXME: Move to `target_link_options`
+    -lbenchmark                      # FIXME: Move to `target_link_options`
+    LLVMSupport
+    Threads::Threads
+)
 fix_rtti(libc-benchmark)
 
 add_libc_benchmark_unittest(libc-benchmark-test
     SRCS LibcBenchmarkTest.cpp
     DEPENDS libc-benchmark
 )
 
 # libc-memory-benchmark