Make spl directory setable when building rpms and add --buildroot

This adds ability to set the location of spl via defines when
building from the spec files.  This is useful for build systems
that build spl and zfs together without installing the actual rpms.

Signed-off-by: Nathaniel Clark <Nathaniel.Clark@misrule.us>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1486

scripts/kmodtool

@@ -37,6 +37,7 @@ kernel_versions_to_build_for=
 prefix=
 filterfile=
 target=
+buildroot=
 
 error_out()
 {
@@ -305,9 +306,9 @@ print_customrpmtemplate ()
 {
 	for kernel in ${1}
 	do
-		if 	[[ -e "/usr/src/kernels/${kernel}" ]] ; then
+		if [[ -e "${buildroot}/usr/src/kernels/${kernel}" ]] ; then
 			# this looks like a Fedora/RH kernel -- print a normal template (which includes the proper BR) and be happy :)
-			kernel_versions="${kernel_versions}${kernel}___%{_usrsrc}/kernels/${kernel} "
+			kernel_versions="${kernel_versions}${kernel}___${buildroot}%{_usrsrc}/kernels/${kernel} "
 
 			# parse kernel versions string and print template
 			local kernel_verrelarch=${kernel%%${kernels_known_variants}}
@@ -382,7 +383,6 @@ myprog_help ()
 	echo "Usage: $(basename ${0}) [OPTIONS]"
 	echo $'\n'"Creates a template to be used during kmod building"
 	echo $'\n'"Available options:"
-	# FIXME	echo " --datadir <dir>     -- look for our shared files in <dir>"
 	echo " --filterfile <file>  -- filter the results with grep --file <file>"
 	echo " --for-kernels <list> -- created templates only for these kernels"
 	echo " --kmodname <file>    -- name of the kmod (required)"
@@ -390,6 +390,7 @@ myprog_help ()
 	echo " --noakmod            -- no akmod package"
 	echo " --repo <name>        -- use buildsys-build-<name>-kerneldevpkgs"
 	echo " --target <arch>      -- target-arch (required)"
+	echo " --buildroot <dir>    -- Build root (place to look for build files)"
 }
 
 while [ "${1}" ] ; do
@@ -478,6 +479,11 @@ while [ "${1}" ] ; do
 			shift
 			build_kernels="current"
 			;;
+		--buildroot)
+			shift
+			buildroot="${1}"
+			shift
+			;;
 		--help)
 			myprog_help
 			exit 0