Use CCache if available (#2866)

Summary: Pull Request resolved: https://github.com/pytorch/audio/pull/2866

Reviewed By: carolineechen

Differential Revision: D42349474

Pulled By: mthrok

fbshipit-source-id: 31455184031fff52719ef829e40bb1e09e11b0e7

CMakeLists.txt

@@ -141,6 +141,16 @@ else()
 endif()
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${warning_flags} ${TORCH_CXX_FLAGS}")
 
+find_program(CCACHE_PROGRAM ccache)
+if(CCACHE_PROGRAM)
+  message(STATUS "Found ccache")
+  set(CMAKE_C_COMPILER_LAUNCHER "${CCACHE_PROGRAM}")
+  set(CMAKE_CXX_COMPILER_LAUNCHER "${CCACHE_PROGRAM}")
+  set(CMAKE_CUDA_COMPILER_LAUNCHER "${CCACHE_PROGRAM}")
+else()
+  message(STATUS "Could not find ccache. Consider installing ccache to speed up compilation.")
+endif()
+
 add_subdirectory(third_party)
 add_subdirectory(torchaudio/csrc)
 if (BUILD_SOX)