diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -268,31 +268,6 @@
 	find_library(RT_LIBRARY rt)
 	target_link_libraries(util ${RT_LIBRARY})
 
-	#__fdelt_chk's params and return type have changed from long unsigned int to
-	# long int. See which one is present here.
-	include(CheckPrototypeDefinition)
-
-	set(CMAKE_REQUIRED_DEFINITIONS -D_FORTIFY_SOURCE=2)
-	# Without some optimization the compiler won't detect the prototype conflict
-	# and always succeed to build.
-	set(CMAKE_REQUIRED_FLAGS -O2)
-
-	check_prototype_definition(
-		__fdelt_warn
-		"extern long unsigned int __fdelt_warn(long unsigned int a)"
-		"0"
-		"sys/select.h"
-		FDELT_PROTOTYPE_LONG_UNSIGNED_INT
-	)
-
-	if(FDELT_PROTOTYPE_LONG_UNSIGNED_INT)
-		set(FDELT_TYPE "long unsigned int")
-	else()
-		set(FDELT_TYPE "long int")
-	endif()
-
-	target_compile_definitions(util PRIVATE "-DFDELT_TYPE=${FDELT_TYPE}")
-
 	# Wrap some glibc functions with ours
 	add_linker_flags(-Wl,--wrap=__divmoddi4)
 	add_linker_flags(-Wl,--wrap=log2f)
diff --git a/src/config/CMakeLists.txt b/src/config/CMakeLists.txt
--- a/src/config/CMakeLists.txt
+++ b/src/config/CMakeLists.txt
@@ -170,6 +170,29 @@
     }
 " HAVE_FUNC_ATTRIBUTE_DLLEXPORT)
 
+#__fdelt_chk's params and return type have changed from long unsigned int to
+# long int. See which one is present here.
+include(CheckPrototypeDefinition)
+
+set(CMAKE_REQUIRED_DEFINITIONS -D_FORTIFY_SOURCE=2)
+# Without some optimization the compiler won't detect the prototype conflict
+# and always succeed to build.
+set(CMAKE_REQUIRED_FLAGS -O2)
+
+check_prototype_definition(
+	__fdelt_warn
+	"extern long unsigned int __fdelt_warn(long unsigned int a)"
+	"0"
+	"sys/select.h"
+	FDELT_PROTOTYPE_LONG_UNSIGNED_INT
+)
+
+if(FDELT_PROTOTYPE_LONG_UNSIGNED_INT)
+	set(FDELT_TYPE "long unsigned int")
+else()
+	set(FDELT_TYPE "long int")
+endif()
+
 # OpenSSL functionality
 set(CMAKE_REQUIRED_INCLUDES ${OPENSSL_CRYPTO_INCLUDES})
 set(CMAKE_REQUIRED_LIBRARIES ${OPENSSL_CRYPTO_LIBRARY})
diff --git a/src/config/bitcoin-config.h.cmake.in b/src/config/bitcoin-config.h.cmake.in
--- a/src/config/bitcoin-config.h.cmake.in
+++ b/src/config/bitcoin-config.h.cmake.in
@@ -60,6 +60,8 @@
 
 #cmakedefine HAVE_DECL_EVP_MD_CTX_NEW 1
 
+#define FDELT_TYPE ${FDELT_TYPE}
+
 #cmakedefine ENABLE_WALLET 1
 #cmakedefine ENABLE_ZMQ 1