diff --git a/lib/csu/aarch64/Makefile b/lib/csu/aarch64/Makefile
--- a/lib/csu/aarch64/Makefile
+++ b/lib/csu/aarch64/Makefile
@@ -3,7 +3,6 @@
 .PATH: ${.CURDIR:H}/common
 
 CFLAGS+=	-I${.CURDIR}
-CFLAGS+=	-DCRT_IRELOC_RELA
 
 CRT1OBJS+=	crt1_s.o
 
diff --git a/lib/csu/aarch64/crt1_c.c b/lib/csu/aarch64/crt1_c.c
--- a/lib/csu/aarch64/crt1_c.c
+++ b/lib/csu/aarch64/crt1_c.c
@@ -35,16 +35,7 @@
 #include <stdlib.h>
 
 #include "libc_private.h"
-#include "ignore_init.c"
-
-#ifdef GCRT
-extern void _mcleanup(void);
-extern void monstartup(void *, void *);
-extern int eprol;
-extern int etext;
-#endif
-
-extern long * _end;
+#include "csu_common.h"
 
 void __start(int, char **, char **, void (*)(void));
 
@@ -52,22 +43,5 @@
 void
 __start(int argc, char *argv[], char *env[], void (*cleanup)(void))
 {
-
-	handle_argv(argc, argv, env);
-
-	if (&_DYNAMIC != NULL)
-		atexit(cleanup);
-	else {
-		process_irelocs();
-		_init_tls();
-	}
-
-#ifdef GCRT
-	atexit(_mcleanup);
-	monstartup(&eprol, &etext);
-__asm__("eprol:");
-#endif
-
-	handle_static_init(argc, argv, env);
-	exit(main(argc, argv, env));
+	__libc_start1(argc, argc, env, cleanup, main);
 }
diff --git a/lib/csu/amd64/Makefile b/lib/csu/amd64/Makefile
--- a/lib/csu/amd64/Makefile
+++ b/lib/csu/amd64/Makefile
@@ -3,6 +3,6 @@
 .PATH: ${.CURDIR:H}/common
 
 CFLAGS+=	-I${.CURDIR}
-CFLAGS+=	-fno-omit-frame-pointer -DCRT_IRELOC_RELA
+CFLAGS+=	-fno-omit-frame-pointer
 
 .include <bsd.lib.mk>
diff --git a/lib/csu/amd64/crt1_c.c b/lib/csu/amd64/crt1_c.c
--- a/lib/csu/amd64/crt1_c.c
+++ b/lib/csu/amd64/crt1_c.c
@@ -29,17 +29,8 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <stdlib.h>
-
 #include "libc_private.h"
-#include "ignore_init.c"
-
-#ifdef GCRT
-extern void _mcleanup(void);
-extern void monstartup(void *, void *);
-extern int eprol;
-extern int etext;
-#endif
+#include "csu_common.h"
 
 void _start(char **, void (*)(void));
 
@@ -54,21 +45,10 @@
 	argc = *(long *)(void *)ap;
 	argv = ap + 1;
 	env = ap + 2 + argc;
-	handle_argv(argc, argv, env);
-
-	if (&_DYNAMIC != NULL) {
-		atexit(cleanup);
-	} else {
-		process_irelocs();
-		_init_tls();
-	}
-
 #ifdef GCRT
-	atexit(_mcleanup);
-	monstartup(&eprol, &etext);
+	__libc_start1_gcrt(argc, argv, env, cleanup, main, &eprol, &etext);
 __asm__("eprol:");
+#else
+	__libc_start1(argc, argv, env, cleanup, main);
 #endif
-
-	handle_static_init(argc, argv, env);
-	exit(main(argc, argv, env));
 }
diff --git a/lib/csu/common/csu_common.h b/lib/csu/common/csu_common.h
new file mode 100644
--- /dev/null
+++ b/lib/csu/common/csu_common.h
@@ -0,0 +1,36 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright 1996-1998 John D. Polstra.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+char **environ;
+const char *__progname = "";
+
+#ifdef GCRT
+extern int eprol;
+extern int etext;
+#endif
+
+extern int main(int, char **, char **);
diff --git a/lib/csu/i386/Makefile b/lib/csu/i386/Makefile
--- a/lib/csu/i386/Makefile
+++ b/lib/csu/i386/Makefile
@@ -3,7 +3,6 @@
 .PATH: ${.CURDIR:H}/common
 
 CFLAGS+=	-I${.CURDIR}
-CFLAGS+=	-DCRT_IRELOC_REL
 
 CRT1OBJS+=	crt1_s.o
 
diff --git a/lib/csu/i386/crt1_c.c b/lib/csu/i386/crt1_c.c
--- a/lib/csu/i386/crt1_c.c
+++ b/lib/csu/i386/crt1_c.c
@@ -29,20 +29,10 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <stdlib.h>
-
 #include "libc_private.h"
-#include "ignore_init.c"
-
-extern void _start(char *, ...);
-
-#ifdef GCRT
-extern void _mcleanup(void);
-extern void monstartup(void *, void *);
-extern int eprol;
-extern int etext;
-#endif
+#include "csu_common.h"
 
+void _start(char *, ...);
 void _start1(void (*)(void), int, char *[]) __dead2;
 
 /* The entry function, C part. */
@@ -52,22 +42,12 @@
 	char **env;
 
 	env = argv + argc + 1;
-	handle_argv(argc, argv, env);
-	if (&_DYNAMIC != NULL) {
-		atexit(cleanup);
-	} else {
-		process_irelocs();
-		_init_tls();
-	}
-
 #ifdef GCRT
-	atexit(_mcleanup);
-	monstartup(&eprol, &etext);
+	__libc_start1_gcrt(argc, argv, env, cleanup, main, &eprol, &etext);
 __asm__("eprol:");
+#else
+	__libc_start1(argc, argv, env, cleanup, main);
 #endif
-
-	handle_static_init(argc, argv, env);
-	exit(main(argc, argv, env));
 }
 
 __asm(".hidden	_start1");
diff --git a/lib/libc/Makefile b/lib/libc/Makefile
--- a/lib/libc/Makefile
+++ b/lib/libc/Makefile
@@ -93,6 +93,7 @@
 NOASM=
 
 .include "${LIBC_SRCTOP}/${LIBC_ARCH}/Makefile.inc"
+.include "${LIBC_SRCTOP}/csu/Makefile.inc"
 .include "${LIBC_SRCTOP}/db/Makefile.inc"
 .include "${LIBC_SRCTOP}/compat-43/Makefile.inc"
 .include "${LIBC_SRCTOP}/gdtoa/Makefile.inc"
diff --git a/lib/libc/csu/Makefile.inc b/lib/libc/csu/Makefile.inc
new file mode 100644
--- /dev/null
+++ b/lib/libc/csu/Makefile.inc
@@ -0,0 +1,10 @@
+#
+
+.PATH: ${LIBC_SRCTOP}/csu
+.include "${LIBC_SRCTOP}/csu/${LIBC_ARCH}/Makefile.inc"
+
+SRCS+= \
+	 ignore_init.c
+
+CFLAGS+= -I${LIBC_SRCTOP}/csu/${LIBC_ARCH}
+SYM_MAPS+=${LIBC_SRCTOP}/csu/Symbol.map
diff --git a/lib/libc/csu/Symbol.map b/lib/libc/csu/Symbol.map
new file mode 100644
--- /dev/null
+++ b/lib/libc/csu/Symbol.map
@@ -0,0 +1,4 @@
+FBSD_1.7 {
+	__libc_start1;
+	__libc_start1_gcrt;
+};
diff --git a/lib/libc/csu/aarch64/Makefile.inc b/lib/libc/csu/aarch64/Makefile.inc
new file mode 100644
--- /dev/null
+++ b/lib/libc/csu/aarch64/Makefile.inc
@@ -0,0 +1,3 @@
+#
+
+CFLAGS+=	-DCRT_IRELOC_RELA
diff --git a/lib/csu/aarch64/reloc.c b/lib/libc/csu/aarch64/reloc.c
rename from lib/csu/aarch64/reloc.c
rename to lib/libc/csu/aarch64/reloc.c
diff --git a/lib/libc/csu/amd64/Makefile.inc b/lib/libc/csu/amd64/Makefile.inc
new file mode 100644
--- /dev/null
+++ b/lib/libc/csu/amd64/Makefile.inc
@@ -0,0 +1,3 @@
+#
+
+CFLAGS+=	-DCRT_IRELOC_RELA
diff --git a/lib/csu/amd64/reloc.c b/lib/libc/csu/amd64/reloc.c
rename from lib/csu/amd64/reloc.c
rename to lib/libc/csu/amd64/reloc.c
diff --git a/lib/libc/csu/i386/Makefile.inc b/lib/libc/csu/i386/Makefile.inc
new file mode 100644
--- /dev/null
+++ b/lib/libc/csu/i386/Makefile.inc
@@ -0,0 +1,3 @@
+#
+
+CFLAGS+=	-DCRT_IRELOC_REL
diff --git a/lib/csu/i386/reloc.c b/lib/libc/csu/i386/reloc.c
rename from lib/csu/i386/reloc.c
rename to lib/libc/csu/i386/reloc.c
diff --git a/lib/csu/common/ignore_init.c b/lib/libc/csu/ignore_init.c
rename from lib/csu/common/ignore_init.c
rename to lib/libc/csu/ignore_init.c
--- a/lib/csu/common/ignore_init.c
+++ b/lib/libc/csu/ignore_init.c
@@ -31,8 +31,8 @@
 #include <sys/param.h>
 #include <sys/elf.h>
 #include <sys/elf_common.h>
-
-extern int main(int, char **, char **);
+#include <stdlib.h>
+#include "libc_private.h"
 
 extern void (*__preinit_array_start[])(int, char **, char **) __hidden;
 extern void (*__preinit_array_end[])(int, char **, char **) __hidden;
@@ -79,9 +79,6 @@
 #error "Define platform reloc type"
 #endif
 
-char **environ;
-const char *__progname = "";
-
 static void
 finalizer(void)
 {
@@ -97,7 +94,7 @@
 	_fini();
 }
 
-static inline void
+static void
 handle_static_init(int argc, char **argv, char **env)
 {
 	void (*fn)(int, char **, char **);
@@ -123,7 +120,10 @@
 	}
 }
 
-static inline void
+extern char **environ;
+extern const char *__progname;
+
+static void
 handle_argv(int argc, char *argv[], char **env)
 {
 	const char *s;
@@ -138,3 +138,45 @@
 		}
 	}
 }
+
+void
+__libc_start1(int argc, char *argv[], char *env[], void (*cleanup)(void),
+    int (*mainX)(int, char *[], char *[]))
+{
+	handle_argv(argc, argv, env);
+
+	if (&_DYNAMIC != NULL)
+		atexit(cleanup);
+	else {
+		process_irelocs();
+		_init_tls();
+	}
+
+	handle_static_init(argc, argv, env);
+	exit(mainX(argc, argv, env));
+}
+
+/* XXXKIB _mcleanup and monstartup defs */
+extern void _mcleanup(void);
+extern void monstartup(void *, void *);
+
+void
+__libc_start1_gcrt(int argc, char *argv[], char *env[],
+    void (*cleanup)(void), int (*mainX)(int, char *[], char *[]),
+    int *eprolp, int *etextp)
+{
+	handle_argv(argc, argv, env);
+
+	if (&_DYNAMIC != NULL)
+		atexit(cleanup);
+	else {
+		process_irelocs();
+		_init_tls();
+	}
+
+	atexit(_mcleanup);
+	monstartup(eprolp, etextp);
+
+	handle_static_init(argc, argv, env);
+	exit(mainX(argc, argv, env));
+}
diff --git a/lib/libc/include/libc_private.h b/lib/libc/include/libc_private.h
--- a/lib/libc/include/libc_private.h
+++ b/lib/libc/include/libc_private.h
@@ -249,6 +249,12 @@
 int _yp_check(char **);
 #endif
 
+void __libc_start1(int, char *[], char *[],
+    void (*)(void), int (*)(int, char *[], char *[])) __dead2;
+void __libc_start1_gcrt(int, char *[], char *[],
+    void (*)(void), int (*)(int, char *[], char *[]),
+    int *, int *) __dead2;
+
 /*
  * Initialise TLS for static programs
  */