Couldn't get the copy command to work for yaml.h, so switched to configure_file

CMakeLists.txt

@@ -52,6 +52,16 @@ option(APPLE_UNIVERSAL_BIN "Apple: Build universal binary" OFF)
 option(MSVC_SHARED_RT "MSVC: Build with shared runtime libs (/MD)" ON)
 option(MSVC_STHREADED_RT "MSVC: Build with single-threaded static runtime libs (/ML until VS .NET 2003)" OFF)
 
+###
+### Configure the main header
+###
+if(YAML_CPP_BUILD_OLD_API)
+	set(API_DEFINE "#define YAML_CPP_OLD_API")
+else()
+	set(API_DEFINE "#undef YAML_CPP_OLD_API")
+endif()
+
+configure_file(${YAML_CPP_SOURCE_DIR}/include/yaml-cpp/yaml.h.cmake ${YAML_CPP_SOURCE_DIR}/include/yaml-cpp/yaml.h @ONLY)
 
 ###
 ### Sources, headers, directories and libs
@@ -79,22 +89,10 @@ if(YAML_CPP_BUILD_OLD_API)
 	list(APPEND public_headers ${common_public_headers} ${old_api_public_headers})
 	list(APPEND private_headers ${common_private_headers} ${old_api_private_headers})
 	add_definitions(-DYAML_CPP_OLD_API)
-
-	ADD_CUSTOM_COMMAND(
-		OUTPUT ${CMAKE_CURRENT_SOURCE_DIR}/include/yaml-cpp/yaml.h
-		COMMAND ${CMAKE_COMMAND} copy ${CMAKE_CURRENT_SOURCE_DIR}/include/yaml-cpp/yaml-old-api.h ${CMAKE_CURRENT_SOURCE_DIR}/include/yaml-cpp/yaml.h
-		DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/include/yaml-cpp/yaml-old-api.h
-	)
 else()
 	list(APPEND sources ${common_sources} ${new_api_sources})
 	list(APPEND public_headers ${common_public_headers} ${new_api_public_headers})
 	list(APPEND private_headers ${common_private_headers} ${new_api_private_headers})
-
-	ADD_CUSTOM_COMMAND(
-		OUTPUT ${CMAKE_CURRENT_SOURCE_DIR}/include/yaml-cpp/yaml.h
-		COMMAND ${CMAKE_COMMAND} copy ${CMAKE_CURRENT_SOURCE_DIR}/include/yaml-cpp/yaml-new-api.h ${CMAKE_CURRENT_SOURCE_DIR}/include/yaml-cpp/yaml.h
-		DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/include/yaml-cpp/yaml-new-api.h
-	)
 endif()
 
 if(YAML_CPP_BUILD_CONTRIB)

include/yaml-cpp/yaml-old-api.h

-#ifndef YAML_H_62B23520_7C8E_11DE_8A39_0800200C9A66
-#define YAML_H_62B23520_7C8E_11DE_8A39_0800200C9A66
-
-#if defined(_MSC_VER) || (defined(__GNUC__) && (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) || (__GNUC__ >= 4)) // GCC supports "pragma once" correctly since 3.4
-#pragma once
-#endif
-
-
-#include "yaml-cpp/parser.h"
-#include "yaml-cpp/emitter.h"
-#include "yaml-cpp/stlemitter.h"
-#include "yaml-cpp/exceptions.h"
-
-#include "yaml-cpp/old-api/node.h"
-#include "yaml-cpp/old-api/stlnode.h"
-#include "yaml-cpp/old-api/iterator.h"
-
-#endif // YAML_H_62B23520_7C8E_11DE_8A39_0800200C9A66

include/yaml-cpp/yaml-new-api.h → include/yaml-cpp/yaml.h.cmake

@@ -5,12 +5,21 @@
 #pragma once
 #endif
 
+@API_DEFINE@
 
 #include "yaml-cpp/parser.h"
 #include "yaml-cpp/emitter.h"
 #include "yaml-cpp/stlemitter.h"
 #include "yaml-cpp/exceptions.h"
 
+#ifdef YAML_CPP_OLD_API
+
+#include "yaml-cpp/old-api/node.h"
+#include "yaml-cpp/old-api/stlnode.h"
+#include "yaml-cpp/old-api/iterator.h"
+
+#else
+
 #include "yaml-cpp/node/node.h"
 #include "yaml-cpp/node/impl.h"
 #include "yaml-cpp/node/convert.h"
@@ -19,4 +28,6 @@
 #include "yaml-cpp/node/parse.h"
 #include "yaml-cpp/node/emit.h"
 
+#endif // YAML_CPP_OLD_API
+
 #endif // YAML_H_62B23520_7C8E_11DE_8A39_0800200C9A66