cmake: Use set_property( SOURCE ... COMPILE_DEFINITIONS )

instead of set_source_files_properties( ... COMPILE_FLAGS )
to avoid the problem of double escaping quotation marks.

Signed-off-by: Michele Calgaro <michele.calgaro@yahoo.it>
(cherry picked from commit c1b7409de9)

artsc/CMakeLists.txt

@@ -86,7 +86,7 @@ tde_add_library( artsdsp_st SHARED
   DESTINATION ${LIB_INSTALL_DIR}
 )
 
-set_target_properties( artsdsp_st-shared PROPERTIES COMPILE_FLAGS -DARTSC_BACKEND=\\"${LIB_INSTALL_DIR}/libartscbackend.la\\" )
+set_property( TARGET artsdsp_st-shared APPEND PROPERTY COMPILE_DEFINITIONS ARTSC_BACKEND="${LIB_INSTALL_DIR}/libartscbackend.la" )
 
 
 ##### artsc (shared lib) ########################
@@ -98,7 +98,7 @@ tde_add_library( artsc SHARED
   DESTINATION ${LIB_INSTALL_DIR}
 )
 
-set_target_properties( artsc-shared PROPERTIES COMPILE_FLAGS -DARTSC_BACKEND=\\"${LIB_INSTALL_DIR}/libartscbackend.la\\" )
+set_property( TARGET artsc-shared APPEND PROPERTY COMPILE_DEFINITIONS ARTSC_BACKEND="${LIB_INSTALL_DIR}/libartscbackend.la" )
 
 
 ##### artscbackend (shared lib) #################

soundserver/CMakeLists.txt

@@ -165,7 +165,7 @@ tde_add_executable( artswrapper
 # FIXME "artsdpath" seems inconsistent name
 # necessary for artswrapper
 SET( artsdpath  ${BIN_INSTALL_DIR}/artsd )
-set_target_properties( artswrapper PROPERTIES COMPILE_FLAGS -DEXECUTE=\\"${artsdpath}\\" )
+set_property( TARGET artswrapper APPEND PROPERTY COMPILE_DEFINITIONS EXECUTE="${artsdpath}" )
 
 
 ##### artsshell #################################