[PPC][BOLT] Fix build error, copy PPGenInstrInfo.inc to include dir as soon as it is generated, before any compilation step tries to include it

Author: kostasalv

bolt/lib/Target/PowerPC/CMakeLists.txt

@@ -7,10 +7,24 @@ target_include_directories(LLVMBOLTTargetPowerPC PRIVATE
     ${LLVM_SOURCE_DIR}/include
 )
 
+# Ensure the destination directory exists
 file(MAKE_DIRECTORY "${LLVM_BINARY_DIR}/include/llvm/Target/PowerPC")
 
-add_custom_command(TARGET LLVMBOLTTargetPowerPC POST_BUILD
+# Custom command to copy the .inc file when it's generated
+add_custom_command(
+    OUTPUT "${LLVM_BINARY_DIR}/include/llvm/Target/PowerPC/PPCGenInstrInfo.inc"
     COMMAND ${CMAKE_COMMAND} -E copy_if_different
         "${LLVM_BINARY_DIR}/lib/Target/PowerPC/PPCGenInstrInfo.inc"
         "${LLVM_BINARY_DIR}/include/llvm/Target/PowerPC/PPCGenInstrInfo.inc"
-)
+    DEPENDS "${LLVM_BINARY_DIR}/lib/Target/PowerPC/PPCGenInstrInfo.inc"
+    COMMENT "Copying PPCGenInstrInfo.inc to include directory"
+)
+
+# Custom target to represent the copied .inc file
+add_custom_target(
+    BoltCopyPPCGenInstrInfoInc ALL
+    DEPENDS "${LLVM_BINARY_DIR}/include/llvm/Target/PowerPC/PPCGenInstrInfo.inc"
+)
+
+# Make your library depend on the copy
+add_dependencies(LLVMBOLTTargetPowerPC BoltCopyPPCGenInstrInfoInc)