update CMakeList to allow pass a relative path for llvm-config

CMakeLists.txt

@@ -5,26 +5,24 @@ set(CMAKE_PROJECT_DESCRIPTION "Executing CUDA on non-NVIDIA architecture.")
 set(CMAKE_CXX_STANDARD "14")
 
 if(DEFINED LLVM_CONFIG_PATH)
-  if(IS_ABSOLUTE "${LLVM_CONFIG_PATH}")
-    if(EXISTS "${LLVM_CONFIG_PATH}")
-      set(LLVM_CONFIG "${LLVM_CONFIG_PATH}")
-    else()
-      message(FATAL_ERROR "llvm-config is not found in ${LLVM_CONFIG_PATH}")
-    endif()
-    message(STATUS "Using llvm-config: ${LLVM_CONFIG}")
-    execute_process(
-      COMMAND "${LLVM_CONFIG}" "--cxxflags"
-      OUTPUT_VARIABLE LLVM_CXX_FLAG
-      OUTPUT_STRIP_TRAILING_WHITESPACE)
-    execute_process(
-      COMMAND "${LLVM_CONFIG}" "--libdir"
-      OUTPUT_VARIABLE LLVM_LIB_PATH
-      OUTPUT_STRIP_TRAILING_WHITESPACE)
-    execute_process(
-      COMMAND "${LLVM_CONFIG}" "--libs"
-      OUTPUT_VARIABLE LLVM_LINK_FLAG
-      OUTPUT_STRIP_TRAILING_WHITESPACE)
+  if(EXISTS "${LLVM_CONFIG_PATH}")
+    set(LLVM_CONFIG "${LLVM_CONFIG_PATH}")
+  else()
+    message(FATAL_ERROR "llvm-config is not found in ${LLVM_CONFIG_PATH}")
   endif()
+  message(STATUS "Using llvm-config: ${LLVM_CONFIG}")
+  execute_process(
+    COMMAND "${LLVM_CONFIG}" "--cxxflags"
+    OUTPUT_VARIABLE LLVM_CXX_FLAG
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+  execute_process(
+    COMMAND "${LLVM_CONFIG}" "--libdir"
+    OUTPUT_VARIABLE LLVM_LIB_PATH
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+  execute_process(
+    COMMAND "${LLVM_CONFIG}" "--libs"
+    OUTPUT_VARIABLE LLVM_LINK_FLAG
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
 else()
   message(FATAL_ERROR "llvm-config is required")
 endif()