Use the asmjit and cpuinfo packages.

diff --git i/CMakeLists.txt w/CMakeLists.txt
index e645fc81..9fc95a17 100644
--- i/CMakeLists.txt
+++ w/CMakeLists.txt
@@ -53,7 +53,7 @@ endfunction()
 project(
   fbgemm
   VERSION 1.4.0
-  LANGUAGES CXX)
+  LANGUAGES C CXX)
 
 # Add C++ compiler flag detection
 include(CheckCXXCompilerFlag)
@@ -447,7 +447,22 @@ install(
 # Asmjit Target
 ################################################################################

+find_package(asmjit REQUIRED)
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(libcpuinfo REQUIRED IMPORTED_TARGET libcpuinfo)
+
+# Keep the upstream target names expected by DEPS throughout this file,
+# while wiring them to system-installed packages.
 if(NOT TARGET asmjit)
+  add_library(asmjit INTERFACE IMPORTED)
+  target_link_libraries(asmjit INTERFACE asmjit::asmjit)
+endif()
+if(NOT TARGET cpuinfo)
+  add_library(cpuinfo INTERFACE IMPORTED)
+  target_link_libraries(cpuinfo INTERFACE PkgConfig::libcpuinfo)
+endif()
+
+if(FALSE)
   # Download asmjit from github if ASMJIT_SRC_DIR is not specified.
   if(NOT DEFINED ASMJIT_SRC_DIR)
     set(ASMJIT_SRC_DIR "${FBGEMM_SOURCE_DIR}/external/asmjit"
@@ -469,7 +484,7 @@ endif()
 # Cpuinfo Target
 ################################################################################
 
-if(NOT TARGET cpuinfo)
+if(FALSE)
   #Download cpuinfo from github if CPUINFO_SOURCE_DIR is not specified.
   if(NOT DEFINED CPUINFO_SOURCE_DIR)
     set(CPUINFO_SOURCE_DIR "${FBGEMM_SOURCE_DIR}/external/cpuinfo"
diff --git i/test/CMakeLists.txt w/test/CMakeLists.txt
index d687e8dc..546540dd 100644
--- i/test/CMakeLists.txt
+++ w/test/CMakeLists.txt
@@ -10,7 +10,7 @@
 
 find_package(GTest)
 
-if(NOT GTest_FOUND)
+if(FALSE)
   # Download Googletest framework from github if
   # GOOGLETEST_SOURCE_DIR is not specified.
   set(INSTALL_GTEST OFF)
