Index: head/Mk/Uses/mono.mk
===================================================================
--- head/Mk/Uses/mono.mk
+++ head/Mk/Uses/mono.mk
@@ -10,6 +10,8 @@
 #
 # Arguments:
 #
+# build		Specifies that mono is only a build-time dependency.
+#
 # nuget		Specifies that the port uses nuget packages.
 #
 #		EXTRACT_ONLY is conditionally overridden to exclude all
@@ -71,8 +73,8 @@
 .if !defined(_INCLUDE_USES_MONO_MK)
 _INCLUDE_USES_MONO_MK=	yes
 
-.if !empty(mono_ARGS:Nnuget)
-IGNORE=	USES=mono only supports an optional nuget argument
+.if !empty(mono_ARGS:Nnuget:Nbuild)
+IGNORE=	USES=mono only supports optional arguments nuget and build
 .endif
 
 # Set the location of the .wapi directory so we write to a location we
@@ -81,7 +83,9 @@
 CONFIGURE_ENV+=		MONO_SHARED_DIR="${MONO_SHARED_DIR}"
 MAKE_ENV+=		MONO_SHARED_DIR="${MONO_SHARED_DIR}" TZ=UTC
 BUILD_DEPENDS+=		mono:lang/mono
+.if empty(mono_ARGS:Mbuild)
 RUN_DEPENDS+=		mono:lang/mono
+.endif
 
 # Set the location that webaps served by XSP should use.
 XSP_DOCROOT=		${PREFIX}/www/xsp