scripts: pass on options such as set -x to child processes

When re-running makepkg for fakeroot, if `bash -x makepkg` was used this
is lost. Fix by encoding the current set of options explicitly in the
invocation, both for makepkg and for the wrapper used to test scripts
inside the source tree.

Also change to use ${BASH_SOURCE[0]} instead of $0 as the latter can be
anything the parent process wants, while the former is explicitly set by
bash itself to the filepath of the script.

See http://mywiki.wooledge.org/BashFAQ/028

Signed-off-by: Eli Schwartz <eschwartz@archlinux.org>
Signed-off-by: Allan McRae <allan@archlinux.org>

scripts/makepkg.sh.in

@@ -181,7 +181,7 @@ clean_up() {
 
 enter_fakeroot() {
 	msg "$(gettext "Entering %s environment...")" "fakeroot"
-	fakeroot -- $0 -F "${ARGLIST[@]}" || exit $?
+	fakeroot -- bash -$- "${BASH_SOURCE[0]}" -F "${ARGLIST[@]}" || exit $?
 }
 
 # Automatically update pkgver variable if a pkgver() function is provided

scripts/wrapper.sh.in

@@ -20,4 +20,4 @@
 
 DIR="@PWD@"
 
-LIBRARY="$DIR"/libmakepkg exec "$DIR"/.lib/@PROGNAME@ "$@"
+LIBRARY="$DIR"/libmakepkg exec bash -$- "$DIR"/.lib/@PROGNAME@ "$@"