put cmake cpuinfo vars into cmake cache

Summary:
Put two CMAKE vars related with cpuinfo into CMAKE CACHE so that their values can be defined from command line.
CPUINFO_LIBRARY_TYPE
CPUINFO_RUNTIME_TYPE

Reviewed By: jianyuh

Differential Revision: D19665130

fbshipit-source-id: dda96da0f6b39038fa3f610e14d03e6d8b769c3a

CMakeLists.txt

@@ -221,9 +221,9 @@ if(NOT TARGET cpuinfo)
   set(CPUINFO_BUILD_UNIT_TESTS OFF CACHE BOOL "Do not build cpuinfo unit tests")
   set(CPUINFO_BUILD_MOCK_TESTS OFF CACHE BOOL "Do not build cpuinfo mock tests")
   set(CPUINFO_BUILD_BENCHMARKS OFF CACHE BOOL "Do not build cpuinfo benchmarks")
-  set(CPUINFO_LIBRARY_TYPE static)
+  set(CPUINFO_LIBRARY_TYPE static CACHE string "Set lib type to static")
   #Select static runtime, needed for static build for MSVC
-  set(CPUINFO_RUNTIME_TYPE static)
+  set(CPUINFO_RUNTIME_TYPE static CACHE string "Set runtime to static")
   add_subdirectory("${CPUINFO_SOURCE_DIR}" "${FBGEMM_BINARY_DIR}/cpuinfo")
   set_property(TARGET cpuinfo PROPERTY POSITION_INDEPENDENT_CODE ON)
 endif()