Detect whether __COUNTER__ is available

fixes #7040

CMakeLists.txt

@@ -113,8 +113,17 @@ endif()
 set(LIBRARY_OUTPUT_PATH ${CMAKE_BINARY_DIR}/Bin/${CMAKE_BUILD_TYPE} CACHE PATH "Library output path")
 set(EXECUTABLE_OUTPUT_PATH ${CMAKE_BINARY_DIR}/Bin/${CMAKE_BUILD_TYPE} CACHE PATH "Executable output path")
 
+include(CheckSymbolExists)
 include(CheckFunctionExists)
 include(CheckLibraryExists)
+
+check_symbol_exists(__COUNTER__ "" HAVE_COUNTER_MACRO)
+
+if(NOT HAVE_COUNTER_MACRO AND ICINGA2_UNITY_BUILD)
+  message(STATUS "Your C/C++ compiler does not support the __COUNTER__ macro. Disabling unity build.")
+  set(ICINGA2_UNITY_BUILD FALSE)
+endif()
+
 check_function_exists(vfork HAVE_VFORK)
 check_function_exists(backtrace_symbols HAVE_BACKTRACE_SYMBOLS)
 check_function_exists(pipe2 HAVE_PIPE2)

config.h.cmake

@@ -1,6 +1,7 @@
 #ifndef CONFIG_H
 #define CONFIG_H
 
+#cmakedefine HAVE_COUNTER_MACRO
 #cmakedefine HAVE_BACKTRACE_SYMBOLS
 #cmakedefine HAVE_PIPE2
 #cmakedefine HAVE_VFORK

lib/base/initialize.hpp

@@ -35,7 +35,7 @@ inline bool InitializeOnceHelper(InitializeFunc func)
 }
 
 #define INITIALIZE_ONCE(func) \
-	namespace { namespace TOKENPASTE2(io, __COUNTER__) { \
+	namespace { namespace UNIQUE_NAME(io) { \
 		I2_EXPORT bool l_InitializeOnce(icinga::InitializeOnceHelper(func)); \
 	} }
 

lib/base/type.hpp

@@ -100,7 +100,7 @@ struct FactoryHelper
 };
 
 #define REGISTER_TYPE(type) \
-	namespace { namespace TOKENPASTE2(rt, __COUNTER__) { \
+	namespace { namespace UNIQUE_NAME(rt) { \
 		void RegisterType(void) \
 		{ \
 			icinga::Type *t = new TypeImpl<type>(); \

lib/base/utility.hpp

@@ -33,9 +33,11 @@ namespace icinga
 #define TOKENPASTE(x, y) x ## y
 #define TOKENPASTE2(x, y) TOKENPASTE(x, y)
 
-#if defined(ICINGA2_UNITY_BUILD) && !defined(__COUNTER__)
-#	error "Your compiler needs to support __COUNTER__ in order to do unity builds."
-#endif /* ICINGA2_UNITY_BUILD && !defined(__COUNTER__) */
+#ifdef HAVE_COUNTER_MACRO
+#	define UNIQUE_NAME(prefix) TOKENPASTE2(prefix, __COUNTER__)
+#else /* HAVE_COUNTER_MACRO */
+#	define UNIQUE_NAME(prefix) prefix
+#endif /* HAVE_COUNTER_MACRO */
 
 #ifdef _WIN32
 #define MS_VC_EXCEPTION 0x406D1388