cmake enable ccache for runtime inlined code

src/runtime/inline/CMakeLists.txt

@@ -43,6 +43,13 @@ include_directories(${CMAKE_SOURCE_DIR}/src)
 file(GLOB_RECURSE PYSTON_HEADERS ${CMAKE_SOURCE_DIR}/src/*.h)
 file(GLOB_RECURSE FROM_CPYTHON_HEADERS ${CMAKE_SOURCE_DIR}/from_cpython/*.h)
 
+# set compiler
+if(CCACHE)
+  set(BC_CXX ${CCACHE} ${LLVM_TOOLS_BINARY_DIR}/clang++)
+else()
+  set(BC_CXX ${LLVM_TOOLS_BINARY_DIR}/clang++)
+endif()
+
 # set CXX flags
 set(BC_CXX_FLAGS "")
 if(${CMAKE_BUILD_TYPE} STREQUAL "Debug")
@@ -75,7 +82,7 @@ foreach(BC_SRC ${BC_INLINE_SRCS})
 
   # generate the bitcode for this file
   add_custom_command(OUTPUT ${BC_SRC_BASENAME}.bc
-                     COMMAND ${LLVM_TOOLS_BINARY_DIR}/clang++ ${BC_DEFINES} ${BC_CXX_FLAGS} ${BC_INCLUDES} -c ${BC_SRC_FULLPATH} -o ${BC_SRC_BASENAME}.bc -emit-llvm
+                     COMMAND ${BC_CXX} ${BC_DEFINES} ${BC_CXX_FLAGS} ${BC_INCLUDES} -c ${BC_SRC_FULLPATH} -o ${BC_SRC_BASENAME}.bc -emit-llvm
                      DEPENDS ${BC_SRC_FULLPATH} clang ${PYSTON_HEADERS} ${FROM_CPYTHON_HEADERS}
                      COMMENT "Building LLVM bitcode ${BC_SRC_BASENAME}.bc"
                      VERBATIM)
@@ -92,7 +99,7 @@ foreach(BC_SRC ${BC_INLINE_SRCS})
 
   # compile into a regular object file
   add_custom_command(OUTPUT ${BC_SRC_BASENAME}.o
-                     COMMAND ${LLVM_TOOLS_BINARY_DIR}/clang++ ${BC_DEFINES} ${BC_CXX_FLAGS} ${BC_INCLUDES} -c ${BC_SRC_BASENAME}.pub.bc -o ${BC_SRC_BASENAME}.o
+                     COMMAND ${BC_CXX} ${BC_DEFINES} ${BC_CXX_FLAGS} ${BC_INCLUDES} -c ${BC_SRC_BASENAME}.pub.bc -o ${BC_SRC_BASENAME}.o
                      DEPENDS ${BC_SRC_BASENAME}.pub.bc clang
                      COMMENT "Compiling ${BC_SRC_BASENAME}.pub.bc -> ${BC_SRC_BASENAME}.o"
                      VERBATIM)