[CMake] file depending on a target

[Brandon J. Van Every]

How can I make a file depend on a target?  I have a lexer SILEX.EXE that 
I generate.  I need other files to depend on the existence of SILEX.EXE, 
so that I can lex and create new output.  It seems like 
target-depends-on-target is dealt with, and file-depends-on-file, and 
even target-depends-on-file.  But not file-depends-on-target.

My current headscratching code:

EXE_C_TARGET(silex) # Generates silex.c from silex.scm
ADD_EXECUTABLE(silex ${Chicken_BINARY_DIR}/silex.c)
SET_TARGET_PROPERTIES(silex PROPERTIES COMPILE_FLAGS "${STATIC_FLAGS}")
TARGET_LINK_LIBRARIES(silex libchicken-static)

ADD_CUSTOM_COMMAND(
  OUTPUT ${Chicken_BINARY_DIR}/easyffi.l.silex
  MAIN_DEPENDENCY ${Chicken_SOURCE_DIR}/easyffi.l
  DEPENDS silex
  COMMAND silex ${Chicken_SOURCE_DIR}/easyffi.l 
${Chicken_BINARY_DIR}/easyffi.l.silex
)

ADD_FILE_DEPENDENCIES(${Chicken_BINARY_DIR}/easyffi.c
  ${Chicken_BINARY_DIR}/easyffi.l.silex
)


It seems that "DEPENDS silex" will not refer to the SILEX.EXE target.  
Rather, it thinks it's an ordinary file level dependency.


Cheers,
Brandon Van Every