Migrate to a new way of dealing with building from old revisions of

FreeBSD.  This method attempts to centralize all the necessary hacks
or work arounds in one of two places in the tree (src/Makefile.inc1
and src/tools/build).  We build a small compatibility library
(libbuild.a) as well as selectively installing necessary include
files.  We then include this directory when building host binaries.

This removes all the past release compatibilty hacks from various
places in the tree.  We still build on tip of stable and current.  I
will work with those that want to support more, although I anticipate
it will just work.

Many thanks to ru@, obrien@ and jhb@ for providing valuable input at
various stage of implementation, as well as for working together to
positively effect a change for the better.

6 files changed, 180 insertions, 0 deletions

diff --git a/tools/build/Makefile b/tools/build/Makefile
new file mode 100644
index 0000000..adde04a
--- /dev/null
+++ b/tools/build/Makefile
@@ -0,0 +1,58 @@
+# $FreeBSD$
+
+.PATH: ${.CURDIR}/../../include
+
+LIB=		build
+SRCS=
+INCSGROUPS=	INCS
+INCS=		
+
+BOOTSTRAPPING?=	0
+
+# Some tools need <sys/endian.h>.
+.if !exists(/usr/include/sys/endian.h)
+INCSGROUPS+=	SYSHDRS
+SYSHDRS=	endian.h
+SYSHDRSDIR=	${INCLUDEDIR}/sys
+.endif
+
+# gnu/usr.bin/binutils/ld needs <elf-hints.h>.
+.if !exists(/usr/include/elf-hints.h)
+INCS+=		elf-hints.h
+.endif
+
+# lib/libncurses needs <stdbool.h>.
+.if !exists(/usr/include/stdbool.h)
+INCS+=		stdbool.h
+.endif
+
+# usr.bin/xargs needs <nl_langinfo.h>.
+.if !exists(/usr/include/langinfo.h)
+INCS+=		langinfo.h
+.endif
+
+# gnu/usr.bin/binutils/libiberty needs basename(3).
+.if ( ${BOOTSTRAPPING} < 440000 || \
+    ( ${BOOTSTRAPPING} >= 500000 && ${BOOTSTRAPPING} < 500022 ))
+.PATH: ${.CURDIR}/../../lib/libc/gen
+SRCS+=		basename.c
+.endif
+
+# Some tools need {get,set}progname(3).
+.if ( ${BOOTSTRAPPING} < 440001 || \
+    ( ${BOOTSTRAPPING} >= 500000 && ${BOOTSTRAPPING} < 500023 ))
+SRCS+=		progname.c
+.endif
+
+# install(1) needs strtofflags(3).
+.if ( ${BOOTSTRAPPING} < 400021 || \
+    ( ${BOOTSTRAPPING} >= 500000 && ${BOOTSTRAPPING} < 500007 ))
+.PATH: ${.CURDIR}/../../lib/libc/gen
+SRCS+=		strtofflags.c
+.endif
+
+.if empty(SRCS)
+SRCS=		dummy.c
+.endif
+
+.include <bsd.lib.mk>
diff --git a/tools/build/Makefile.boot b/tools/build/Makefile.boot
new file mode 100644
index 0000000..e489981
--- /dev/null
+++ b/tools/build/Makefile.boot
@@ -0,0 +1,18 @@
+# $FreeBSD$
+
+# FreeBSD didn't always have the __FBSDID() macro in <sys/cdefs.h>.
+.if defined(BOOTSTRAPPING) && \
+    ( ${BOOTSTRAPPING} < 440001 || \
+    ( ${BOOTSTRAPPING} >= 500000 && ${BOOTSTRAPPING} < 500024 ))
+CFLAGS+=	-D__FBSDID=__RCSID
+.endif
+
+CFLAGS+=	-I${WORLDTMP}/usr/include
+DPADD=		${WORLDTMP}/usr/lib/libbuild.a
+LDADD=		-lbuild
+LDFLAGS=	-L${WORLDTMP}/usr/lib
+
+OLD_MAKE_CONF?=	/etc/make.conf
+.if exists(${OLD_MAKE_CONF})
+.include "${OLD_MAKE_CONF}"
+.endif
diff --git a/tools/build/dummy.c b/tools/build/dummy.c
new file mode 100644
index 0000000..b656a03
--- /dev/null
+++ b/tools/build/dummy.c
@@ -0,0 +1,5 @@
+/*
+ * $FreeBSD$
+ *
+ * Empty file to keep linker happy.
+ */
diff --git a/tools/build/endian.h b/tools/build/endian.h
new file mode 100644
index 0000000..dbec545
--- /dev/null
+++ b/tools/build/endian.h
@@ -0,0 +1,57 @@
+/*
+ * $FreeBSD$
+ */
+
+#include <sys/param.h>
+
+#if __FreeBSD_version >= 500034
+#include_next <sys/endian.h>
+#else
+#include <machine/endian.h>
+
+#define	bswap16(x) (uint16_t) \
+	((x >> 8) | (x << 8))
+
+#define	bswap32(x) (uint32_t) \
+	((x >> 24) | ((x >> 8) & 0xff00) | ((x << 8) & 0xff0000) | (x << 24))
+
+#define	bswap64(x) (uint64_t) \
+	((x >> 56) | ((x >> 40) & 0xff00) | ((x >> 24) & 0xff0000) | \
+	((x >> 8) & 0xff000000) | ((x << 8) & ((uint64_t)0xff << 32)) | \
+	((x << 24) & ((uint64_t)0xff << 40)) | \
+	((x << 40) & ((uint64_t)0xff << 48)) | ((x << 56)))
+
+/*
+ * Host to big endian, host to little endian, big endian to host, and little
+ * endian to host byte order functions as detailed in byteorder(9).
+ */
+#if _BYTE_ORDER == _LITTLE_ENDIAN
+#define	htobe16(x)	bswap16((uint16_t)(x))
+#define	htobe32(x)	bswap32((uint32_t)(x))
+#define	htobe64(x)	bswap64((uint64_t)(x))
+#define	htole16(x)	((uint16_t)(x))
+#define	htole32(x)	((uint32_t)(x))
+#define	htole64(x)	((uint64_t)(x))
+
+#define	be16toh(x)	bswap16((uint16_t)(x))
+#define	be32toh(x)	bswap32((uint32_t)(x))
+#define	be64toh(x)	bswap64((uint64_t)(x))
+#define	le16toh(x)	((uint16_t)(x))
+#define	le32toh(x)	((uint32_t)(x))
+#define	le64toh(x)	((uint64_t)(x))
+#else /* _BYTE_ORDER != _LITTLE_ENDIAN */
+#define	htobe16(x)	((uint16_t)(x))
+#define	htobe32(x)	((uint32_t)(x))
+#define	htobe64(x)	((uint64_t)(x))
+#define	htole16(x)	bswap16((uint16_t)(x))
+#define	htole32(x)	bswap32((uint32_t)(x))
+#define	htole64(x)	bswap64((uint64_t)(x))
+
+#define	be16toh(x)	((uint16_t)(x))
+#define	be32toh(x)	((uint32_t)(x))
+#define	be64toh(x)	((uint64_t)(x))
+#define	le16toh(x)	bswap16((uint16_t)(x))
+#define	le32toh(x)	bswap32((uint32_t)(x))
+#define	le64toh(x)	bswap64((uint64_t)(x))
+#endif /* _BYTE_ORDER == _LITTLE_ENDIAN */
+#endif
diff --git a/tools/build/langinfo.h b/tools/build/langinfo.h
new file mode 100644
index 0000000..419c721
--- /dev/null
+++ b/tools/build/langinfo.h
@@ -0,0 +1,17 @@
+/* $FreeBSD$ */
+
+#ifndef LANGINFO_H
+#define LANGINFO_H
+
+#include <sys/cdefs.h>
+
+#define YESEXPR 1
+
+/* xargs only needs yesexpr, so that's all we implement, for english */
+static inline const char *
+nl_langinfo(int type __unused)
+{
+	return ("^[yY]");
+}
+
+#endif /* LANGINFO_H */
diff --git a/tools/build/progname.c b/tools/build/progname.c
new file mode 100644
index 0000000..dc1611e
--- /dev/null
+++ b/tools/build/progname.c
@@ -0,0 +1,25 @@
+/* $FreeBSD$ */
+
+/*
+ * Compat shims for those programs that use this newer interface.  These
+ * are more minimal than their libc bretheren as far as namespaces and
+ * such go because their use is so limited.  Also, the libc versions
+ * have too many depends on libc build environment; it is more of a pain
+ * to set that up than to recreate them here shorn of all the other goo.
+ */
+
+extern const char *__progname;
+
+void
+setprogname(const char *p)
+{
+
+	__progname = p;
+}
+
+const char *
+getprogname(void)
+{
+
+	return (__progname);
+}