Support parallel build trees (VPATH builds)

Build products from an out of tree build should be written
relative to the build directory.  Sources should be referred
to by their locations in the source directory.

This is accomplished by adding the 'src' and 'obj' variables
for the module Makefile.am, using relative paths to reference
source files, and by setting VPATH when source files are not
co-located with the Makefile.  This enables the following:

  $ mkdir build
  $ cd build
  $ ../configure
  $ make -s

This change also has the advantage of resolving the following
warning which is generated by modern versions of automake.

  Makefile.am:00: warning: source file 'xxx' is in a subdirectory,
  Makefile.am:00: but option 'subdir-objects' is disabled

Signed-off-by: Turbo Fredriksson <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Issue zfsonlinux/zfs#1082

6 files changed, 50 insertions, 44 deletions

diff --git a/Makefile.am b/Makefile.am
index 89af931ae..4977448fd 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,9 +1,9 @@
 
 ACLOCAL_AMFLAGS = -I config
 
-include $(top_srcdir)/config/rpm.am
-include $(top_srcdir)/config/deb.am
-include $(top_srcdir)/config/tgz.am
+include config/rpm.am
+include config/deb.am
+include config/tgz.am
 
 SUBDIRS = include rpm
 if CONFIG_USER
@@ -40,11 +40,11 @@ dist-hook:
 		$(distdir)/META
 
 ctags:
-	$(RM) $(top_srcdir)/tags
+	$(RM) tags
 	find $(top_srcdir) -name .git -prune -o -name '*.[hc]' | xargs ctags
 
 etags:
-	$(RM) $(top_srcdir)/TAGS
+	$(RM) TAGS
 	find $(top_srcdir) -name .pc -prune -o -name '*.[hc]' | xargs etags -a
 
 tags: ctags etags
diff --git a/config/rpm.am b/config/rpm.am
index 311c754d4..51a20b3e6 100644
--- a/config/rpm.am
+++ b/config/rpm.am
@@ -51,7 +51,7 @@ rpm-local:
 	mkdir -p $(rpmbuild)/SPECS && \
 	cp ${RPM_SPEC_DIR}/$(rpmspec) $(rpmbuild)/SPECS && \
 	mkdir -p $(rpmbuild)/SOURCES && \
-	cp scripts/kmodtool $(rpmbuild)/SOURCES && \
+	cp $(top_srcdir)/scripts/kmodtool $(rpmbuild)/SOURCES && \
 	cp $(distdir).tar.gz $(rpmbuild)/SOURCES)
 
 srpm-common: dist
diff --git a/include/util/Makefile.am b/include/util/Makefile.am
index b721b5099..e2bf09fb1 100644
--- a/include/util/Makefile.am
+++ b/include/util/Makefile.am
@@ -2,7 +2,7 @@ COMMON_H =
 
 KERNEL_H = \
 	$(top_srcdir)/include/util/qsort.h \
-        $(top_srcdir)/include/util/sscanf.h
+	$(top_srcdir)/include/util/sscanf.h
 
 USER_H =
 
diff --git a/module/spl/Makefile.in b/module/spl/Makefile.in
index d1742448d..a1f1ab823 100644
--- a/module/spl/Makefile.in
+++ b/module/spl/Makefile.in
@@ -1,27 +1,30 @@
 # Makefile.in for spl kernel module
 
+src = @abs_top_srcdir@/module/spl
+obj = @abs_builddir@
+
 MODULE := spl
 EXTRA_CFLAGS = $(SPL_MODULE_CFLAGS) @KERNELCPPFLAGS@
 
 # Solaris porting layer module
 obj-$(CONFIG_SPL) := $(MODULE).o
 
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-proc.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-kmem.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-kmem-cache.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-vmem.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-thread.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-taskq.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-rwlock.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-vnode.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-err.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-kobj.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-generic.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-atomic.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-mutex.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-kstat.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-condvar.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-xdr.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-cred.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-tsd.o
-$(MODULE)-objs += @top_srcdir@/module/spl/spl-zlib.o
+$(MODULE)-objs += spl-proc.o
+$(MODULE)-objs += spl-kmem.o
+$(MODULE)-objs += spl-kmem-cache.o
+$(MODULE)-objs += spl-vmem.o
+$(MODULE)-objs += spl-thread.o
+$(MODULE)-objs += spl-taskq.o
+$(MODULE)-objs += spl-rwlock.o
+$(MODULE)-objs += spl-vnode.o
+$(MODULE)-objs += spl-err.o
+$(MODULE)-objs += spl-kobj.o
+$(MODULE)-objs += spl-generic.o
+$(MODULE)-objs += spl-atomic.o
+$(MODULE)-objs += spl-mutex.o
+$(MODULE)-objs += spl-kstat.o
+$(MODULE)-objs += spl-condvar.o
+$(MODULE)-objs += spl-xdr.o
+$(MODULE)-objs += spl-cred.o
+$(MODULE)-objs += spl-tsd.o
+$(MODULE)-objs += spl-zlib.o
diff --git a/module/splat/Makefile.in b/module/splat/Makefile.in
index f4065196b..680f28492 100644
--- a/module/splat/Makefile.in
+++ b/module/splat/Makefile.in
@@ -1,25 +1,28 @@
 # Makefile.in for splat kernel module
 
+src = @abs_top_srcdir@/module/splat
+obj = @abs_builddir@
+
 MODULE := splat
 EXTRA_CFLAGS = $(SPL_MODULE_CFLAGS) @KERNELCPPFLAGS@
 
 # Solaris Porting LAyer Tests
 obj-$(CONFIG_SPL) := $(MODULE).o
 
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-ctl.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-kmem.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-taskq.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-random.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-mutex.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-condvar.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-thread.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-rwlock.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-time.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-vnode.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-kobj.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-atomic.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-list.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-generic.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-cred.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-zlib.o
-$(MODULE)-objs += @top_srcdir@/module/splat/splat-linux.o
+$(MODULE)-objs += splat-ctl.o
+$(MODULE)-objs += splat-kmem.o
+$(MODULE)-objs += splat-taskq.o
+$(MODULE)-objs += splat-random.o
+$(MODULE)-objs += splat-mutex.o
+$(MODULE)-objs += splat-condvar.o
+$(MODULE)-objs += splat-thread.o
+$(MODULE)-objs += splat-rwlock.o
+$(MODULE)-objs += splat-time.o
+$(MODULE)-objs += splat-vnode.o
+$(MODULE)-objs += splat-kobj.o
+$(MODULE)-objs += splat-atomic.o
+$(MODULE)-objs += splat-list.o
+$(MODULE)-objs += splat-generic.o
+$(MODULE)-objs += splat-cred.o
+$(MODULE)-objs += splat-zlib.o
+$(MODULE)-objs += splat-linux.o
diff --git a/scripts/Makefile.am b/scripts/Makefile.am
index f146ec6e6..a718c4b1a 100644
--- a/scripts/Makefile.am
+++ b/scripts/Makefile.am
@@ -1,4 +1,4 @@
 EXTRA_DIST = check.sh dkms.mkconf dkms.postbuild kmodtool
 
 check:
-	$(top_srcdir)/scripts/check.sh
+	scripts/check.sh