Revert "Experimental support for spec 2017 on Apple platforms"

I accidentally pushed this before review.

This reverts commit 7114cae7cb79b3a20c165bef3a94883155332546.
diff --git a/External/SPEC/CINT2017rate/500.perlbench_r/CMakeLists.txt b/External/SPEC/CINT2017rate/500.perlbench_r/CMakeLists.txt
index 003a293..1addca6 100644
--- a/External/SPEC/CINT2017rate/500.perlbench_r/CMakeLists.txt
+++ b/External/SPEC/CINT2017rate/500.perlbench_r/CMakeLists.txt
@@ -6,8 +6,6 @@
 
 speccpu2017_benchmark(RATE)
 
-add_definitions(-DSPEC_MACOSX_X64)
-
 add_definitions(
   -DPERL_CORE
   -DDOUBLE_SLASHES_SPECIAL=0
diff --git a/External/SPEC/SpecCPU2017.cmake b/External/SPEC/SpecCPU2017.cmake
index 17f7b3d..88a81be 100644
--- a/External/SPEC/SpecCPU2017.cmake
+++ b/External/SPEC/SpecCPU2017.cmake
@@ -154,8 +154,6 @@
       add_definitions(-DSPEC_LINUX_AARCH64)
     elseif (ARCH STREQUAL "x86" AND TARGET_OS STREQUAL "Windows")
       # Windows x86/x64
-    elseif (TARGET_OS STREQUAL "Darwin")
-      add_definitions(-DSPEC_MACOSX)
     else ()
       message("ARCH: ${ARCH}")
       message("TARGET_OS: ${TARGET_OS}")