diff --git a/share/mk/local.dirdeps-options.mk b/share/mk/local.dirdeps-options.mk
--- a/share/mk/local.dirdeps-options.mk
+++ b/share/mk/local.dirdeps-options.mk
@@ -25,4 +25,4 @@
 DIRDEPS.PAM_SUPPORT.yes+= lib/libpam/libpam
 DIRDEPS.TCP_WRAPPERS.yes+= lib/libwrap
 
-
+.-include <site.dirdeps-options.mk>
diff --git a/share/mk/local.dirdeps.mk b/share/mk/local.dirdeps.mk
--- a/share/mk/local.dirdeps.mk
+++ b/share/mk/local.dirdeps.mk
@@ -217,3 +217,5 @@
 CSU_DIR := ${CSU_DIR.${DEP_MACHINE_ARCH}}
 BOOT_MACHINE_DIR:= ${BOOT_MACHINE_DIR.${DEP_MACHINE}}
 KERNEL_NAME:= ${KERNEL_NAME.${DEP_MACHINE}}
+
+.-include <site.dirdeps.mk>
diff --git a/share/mk/local.init.mk b/share/mk/local.init.mk
--- a/share/mk/local.init.mk
+++ b/share/mk/local.init.mk
@@ -36,5 +36,6 @@
 .endif
 
 .-include "src.init.mk"
+.-include <site.init.mk>
 .-include "${.CURDIR}/local.init.mk"
 .endif
diff --git a/share/mk/local.meta.sys.mk b/share/mk/local.meta.sys.mk
--- a/share/mk/local.meta.sys.mk
+++ b/share/mk/local.meta.sys.mk
@@ -25,6 +25,9 @@
 
 # the list of machines we support
 ALL_MACHINE_LIST?= amd64 arm arm64 i386 powerpc riscv
+
+.-include <site.meta.sys.mk>
+
 .for m in ${ALL_MACHINE_LIST:O:u}
 MACHINE_ARCH_LIST.$m?= ${TARGET_ARCHES_${m}:U$m}
 MACHINE_ARCH.$m?= ${MACHINE_ARCH_LIST.$m:[1]}
diff --git a/share/mk/local.sys.env.mk b/share/mk/local.sys.env.mk
--- a/share/mk/local.sys.env.mk
+++ b/share/mk/local.sys.env.mk
@@ -49,3 +49,4 @@
 .endif
 
 .include "src.sys.env.mk"
+.-include <site.sys.env.mk>
diff --git a/share/mk/local.sys.mk b/share/mk/local.sys.mk
--- a/share/mk/local.sys.mk
+++ b/share/mk/local.sys.mk
@@ -52,6 +52,7 @@
 .endif
 
 .include "src.sys.mk"
+.-include <site.sys.mk>
 
 .if ${.MAKE.MODE:Mmeta*} != ""
 # we can afford to use cookies to prevent some targets
diff --git a/share/mk/src.libnames.mk b/share/mk/src.libnames.mk
--- a/share/mk/src.libnames.mk
+++ b/share/mk/src.libnames.mk
@@ -756,6 +756,8 @@
 
 LIBTERMCAPWDIR=	${LIBTINFOWDIR}
 
+.-include <site.src.libnames.mk>
+
 # Default other library directories to lib/libNAME.
 .for lib in ${_LIBRARIES}
 LIB${lib:tu}DIR?=	${OBJTOP}/lib/lib${lib}
diff --git a/share/mk/src.opts.mk b/share/mk/src.opts.mk
--- a/share/mk/src.opts.mk
+++ b/share/mk/src.opts.mk
@@ -242,6 +242,8 @@
 __DEFAULT_DEPENDENT_OPTIONS+= ${var}_SUPPORT/${var}
 .endfor
 
+.-include <site.src.opts.mk>
+
 #
 # Default behaviour of some options depends on the architecture.  Unfortunately
 # this means that we have to test TARGET_ARCH (the buildworld case) as well
diff --git a/share/mk/src.sys.env.mk b/share/mk/src.sys.env.mk
--- a/share/mk/src.sys.env.mk
+++ b/share/mk/src.sys.env.mk
@@ -42,6 +42,8 @@
 .endif
 .endif
 
+.-include <site.src.sys.env.mk>
+
 SRC_ENV_CONF?= /etc/src-env.conf
 .if !empty(SRC_ENV_CONF) && !target(_src_env_conf_included_)
 .-include "${SRC_ENV_CONF}"
@@ -89,6 +91,6 @@
 .endif
 
 .if ${RELDIR:U} == "." && ${.MAKE.LEVEL} == 0
-.sinclude "${.CURDIR}/Makefile.sys.inc"
+.-include "${.CURDIR}/Makefile.sys.inc"
 .endif
 .include <src.sys.obj.mk>