diff --git a/src/config/CMakeLists.txt b/src/config/CMakeLists.txt
--- a/src/config/CMakeLists.txt
+++ b/src/config/CMakeLists.txt
@@ -108,6 +108,7 @@
 
 # Various system libraries
 check_symbol_exists(strnlen "string.h" HAVE_DECL_STRNLEN)
+check_symbol_exists(daemon "unistd.h" HAVE_DECL_DAEMON)
 
 # OpenSSL functionality
 include(BrewHelper)
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
@@ -43,6 +43,7 @@
 #cmakedefine HAVE_DECL___BUILTIN_CLZLL 1
 
 #cmakedefine HAVE_DECL_STRNLEN 1
+#cmakedefine HAVE_DECL_DAEMON 1
 
 #cmakedefine HAVE_DECL_EVP_MD_CTX_NEW 1