diff --git a/Makefile.inc1 b/Makefile.inc1
index 7074d055acd7..2fc9b11e6be0 100644
--- a/Makefile.inc1
+++ b/Makefile.inc1
@@ -123,6 +123,7 @@ SUPFLAGS+=	-h ${SUPHOST}
 .endif
 
 MAKEOBJDIRPREFIX?=	/usr/obj
+OSRELDATE!=	sysctl -n kern.osreldate
 TARGET_ARCH?=	${MACHINE_ARCH}
 .if ${TARGET_ARCH} == ${MACHINE_ARCH}
 TARGET?=	${MACHINE}
@@ -193,7 +194,8 @@ CROSSENV=	MAKEOBJDIRPREFIX=${OBJTREE} \
 BMAKEENV=	MAKEOBJDIRPREFIX=${WORLDTMP} \
 		DESTDIR= \
 		INSTALL="sh ${.CURDIR}/tools/install.sh"
-BMAKE=		${BMAKEENV} ${MAKE} -f Makefile.inc1 -DBOOTSTRAPPING \
+BMAKE=		${BMAKEENV} ${MAKE} -f Makefile.inc1 \
+		BOOTSTRAPPING=${OSRELDATE} \
 		-DNOHTML -DNOINFO -DNOMAN -DNOPIC -DNOPROFILE -DNOSHARED \
 		-DNO_CPU_CFLAGS -DNO_WERROR
 
@@ -201,8 +203,8 @@ BMAKE=		${BMAKEENV} ${MAKE} -f Makefile.inc1 -DBOOTSTRAPPING \
 TMAKEENV=	MAKEOBJDIRPREFIX=${OBJTREE} \
 		DESTDIR= \
 		INSTALL="sh ${.CURDIR}/tools/install.sh"
-TMAKE=		${TMAKEENV} ${MAKE} -f Makefile.inc1 -DBOOTSTRAPPING \
-		-DNO_CPU_CFLAGS
+TMAKE=		${TMAKEENV} ${MAKE} -f Makefile.inc1 \
+		BOOTSTRAPPING=${OSRELDATE} -DNO_CPU_CFLAGS
 
 # cross-tool stage
 XMAKE=		TOOLS_PREFIX=${WORLDTMP} ${BMAKE} -DNO_FORTRAN -DNO_GDB
diff --git a/gnu/usr.bin/binutils/libiberty/Makefile b/gnu/usr.bin/binutils/libiberty/Makefile
index f34be9e2f2ca..c002f6243106 100644
--- a/gnu/usr.bin/binutils/libiberty/Makefile
+++ b/gnu/usr.bin/binutils/libiberty/Makefile
@@ -10,7 +10,9 @@ SRCS=	argv.c choose-temp.c concat.c cp-demangle.c cplus-dem.c \
 	hex.c floatformat.c hashtab.c lbasename.c make-temp-file.c \
 	objalloc.c obstack.c safe-ctype.c xatexit.c xexit.c xmalloc.c \
 	xstrdup.c xstrerror.c
-.if defined(BOOTSTRAPPING)
+.if defined(BOOTSTRAPPING) && \
+    ( ${BOOTSTRAPPING} < 440000 || \
+    ( ${BOOTSTRAPPING} >= 500000 && ${BOOTSTRAPPING} < 500022 ))
 SRCS+=	basename.c
 .endif
 WARNS=	1
diff --git a/kerberos5/lib/libasn1/Makefile b/kerberos5/lib/libasn1/Makefile
index f38c2bfd37f1..3f270e6dcdb3 100644
--- a/kerberos5/lib/libasn1/Makefile
+++ b/kerberos5/lib/libasn1/Makefile
@@ -106,7 +106,9 @@ asn1_compile:					\
 	strupr.c
 	${CC} ${CFLAGS} ${.OODATE} -o ${.TARGET}
 
-.if defined(BOOTSTRAPPING)
+.if defined(BOOTSTRAPPING) && \
+    ( ${BOOTSTRAPPING} < 440001 || \
+    ( ${BOOTSTRAPPING} >= 500000 && ${BOOTSTRAPPING} < 500023 ))
 asn1_compile: getprogname.c setprogname.c
 .endif
 
diff --git a/kerberos5/lib/libhdb/Makefile b/kerberos5/lib/libhdb/Makefile
index 5a433f19baae..0970b1360265 100644
--- a/kerberos5/lib/libhdb/Makefile
+++ b/kerberos5/lib/libhdb/Makefile
@@ -61,7 +61,9 @@ asn1_compile:	parse.o lex.o main.c hash.c symbol.c emalloc.c gen.c \
 		get_window_size.c strupr.c
 	${CC} ${CFLAGS} ${.OODATE} -o ${.TARGET}
 
-.if defined(BOOTSTRAPPING)
+.if defined(BOOTSTRAPPING) && \
+    ( ${BOOTSTRAPPING} < 440001 || \
+    ( ${BOOTSTRAPPING} >= 500000 && ${BOOTSTRAPPING} < 500023 ))
 asn1_compile: getprogname.c setprogname.c
 .endif
 
diff --git a/share/mk/bsd.sys.mk b/share/mk/bsd.sys.mk
index 2988a5be24bb..82196730757f 100644
--- a/share/mk/bsd.sys.mk
+++ b/share/mk/bsd.sys.mk
@@ -55,7 +55,9 @@ CFLAGS		+=	-Werror
 # Allow user-specified additional warning flags
 CFLAGS		+=	${CWARNFLAGS}
 
-# FreeBSD prior to 4.5 didn't have the __FBSDID() macro in <sys/cdefs.h>.
-.if defined(BOOTSTRAPPING)
+# FreeBSD didn't always have the __FBSDID() macro in <sys/cdefs.h>.
+.if defined(BOOTSTRAPPING) && \
+    ( ${BOOTSTRAPPING} < 440001 || \
+    ( ${BOOTSTRAPPING} >= 500000 && ${BOOTSTRAPPING} < 500024 ))
 CFLAGS+=	-D__FBSDID=__RCSID
 .endif
diff --git a/usr.bin/xargs/Makefile b/usr.bin/xargs/Makefile
index 1f258ca68292..1f33228d8035 100644
--- a/usr.bin/xargs/Makefile
+++ b/usr.bin/xargs/Makefile
@@ -5,8 +5,4 @@ PROG=	xargs
 SRCS=	xargs.c strnsubst.c
 WARNS?=	4
 
-.if defined(BOOTSTRAPPING)
-CFLAGS+=-DBOOTSTRAPPING
-.endif
-
 .include <bsd.prog.mk>
diff --git a/usr.bin/xargs/xargs.c b/usr.bin/xargs/xargs.c
index 96ad3b44d482..5414e65f99dd 100644
--- a/usr.bin/xargs/xargs.c
+++ b/usr.bin/xargs/xargs.c
@@ -51,12 +51,13 @@ static char sccsid[] = "@(#)xargs.c	8.1 (Berkeley) 6/6/93";
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <sys/types.h>
+#include <sys/param.h>
 #include <sys/wait.h>
 
 #include <err.h>
 #include <errno.h>
-#ifndef BOOTSTRAPPING
+#if (__FreeBSD_version >= 450002 && __FreeBSD_version < 500000) || \
+    __FreeBSD_version >= 500017
 #include <langinfo.h>
 #endif
 #include <locale.h>
@@ -542,10 +543,11 @@ prompt(void)
 	(void)fflush(stderr);
 	if ((response = fgetln(ttyfp, &rsize)) == NULL ||
 	    regcomp(&cre,
-#ifdef BOOTSTRAPPING
-		"^[yY]",
-#else
+#if (__FreeBSD_version >= 450002 && __FreeBSD_version < 500000) || \
+    __FreeBSD_version >= 500017
 		nl_langinfo(YESEXPR),
+#else
+		"^[yY]",
 #endif
 		REG_BASIC) != 0) {
 		(void)fclose(ttyfp);
diff --git a/usr.bin/xinstall/Makefile b/usr.bin/xinstall/Makefile
index e0886ed7afdb..2ed1eea375c0 100644
--- a/usr.bin/xinstall/Makefile
+++ b/usr.bin/xinstall/Makefile
@@ -6,7 +6,9 @@ PROGNAME=	install
 SRCS=		xinstall.c
 MAN=		install.1
 
-.if defined(BOOTSTRAPPING)
+.if defined(BOOTSTRAPPING) && \
+    ( ${BOOTSTRAPPING} < 400021 || \
+    ( ${BOOTSTRAPPING} >= 500000 && ${BOOTSTRAPPING} < 500007 ))
 .PATH: ${.CURDIR}/../../lib/libc/gen
 SRCS+=		strtofflags.c
 .endif