Proper out-of-source-directory builds with cmake

CMakeLists.txt

@@ -6,16 +6,18 @@ find_package(BISON)
 find_package(FLEX)
 find_package(GLPK)
 
-BISON_TARGET (citip_parser parser.y parser.cxx)
-FLEX_TARGET  (citip_scanner scanner.l scanner.cxx)
+BISON_TARGET (citip_parser parser.y ${CMAKE_CURRENT_BINARY_DIR}/parser.cxx
+              COMPILE_FLAGS --defines=${CMAKE_CURRENT_BINARY_DIR}/parser.hxx)
+FLEX_TARGET  (citip_scanner scanner.l ${CMAKE_CURRENT_BINARY_DIR}/scanner.cxx
+              COMPILE_FLAGS --header-file=${CMAKE_CURRENT_BINARY_DIR}/scanner.hxx)
 ADD_FLEX_BISON_DEPENDENCY(citip_scanner citip_parser)
 
 
-include_directories(${CMAKE_CURRENT_BINARY_DIR})
+include_directories(${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR})
 add_executable(Citip
     main.cpp
     citip.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/parser.cxx
-    ${CMAKE_CURRENT_SOURCE_DIR}/scanner.cxx
+    ${CMAKE_CURRENT_BINARY_DIR}/parser.cxx
+    ${CMAKE_CURRENT_BINARY_DIR}/scanner.cxx
 )
 target_link_libraries(Citip glpk)

Makefile

@@ -17,10 +17,10 @@ Citip: $(OBJS)
 	g++ $(CFLAGS) -o $@ -c $< -std=c++11
 
 parser.cxx: parser.y
-	bison $<
+	bison -o $@ --defines=parser.hxx $<
 
 scanner.cxx: scanner.l
-	flex $<
+	flex -o $@ --header-file=scanner.hxx $<
 
 parser.hxx:  parser.cxx
 scanner.hxx: scanner.cxx

parser.y

@@ -13,9 +13,6 @@
     language easier to extend and the code easier to maintain.
  */
 
-%output  "parser.cxx"
-%defines "parser.hxx"
-
 /* C++ parser interface */
 %skeleton "lalr1.cc"
 %require  "3.0"

scanner.l

@@ -15,9 +15,6 @@
                   yyscan_t yyscanner)                   // scanner object
 */
 
-%option     outfile="scanner.cxx"
-%option header-file="scanner.hxx"
-
  /*
     c++                 generate C++ parser class
     8bit                don't fail on 8-bit input characters