[Libguestfs] [nbdkit PATCH 2/3] maint: Add NBDKIT_GDB support to in-tree nbdkit script

[Eric Blake]

During development, it is handy to use the ./nbdkit script to
automatically pick up the just-built binaries without having
to install things; but using gdb on a script does not work.
Similar to how we already support $NBDKIT_VALGRIND, add support
for $NBDKIT_GDB; and also make the script robust to a value
of $prefix inherited from the environment.

Signed-off-by: Eric Blake <eblake at redhat.com>
---
 nbdkit.in | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/nbdkit.in b/nbdkit.in
index 167d512..6be89ec 100644
--- a/nbdkit.in
+++ b/nbdkit.in
@@ -99,11 +99,16 @@ if [ $verbose ]; then
     echo $b/src/nbdkit "${args[@]}"
 fi

+prefix=
 # If NBDKIT_VALGRIND=1 is set in the environment, then we run
 # the program under valgrind.  This is used by the tests.
+# Similarly, if NBDKIT_GDB=1 is set in the environment, we run
+# the program under gdb, useful during development.
 if [ "$NBDKIT_VALGRIND" ]; then
-    valgrind="@VALGRIND@ --vgdb=no --leak-check=full --error-exitcode=119 --suppressions=$s/valgrind-suppressions --trace-children=no --child-silent-after-fork=yes --run-libc-freeres=no"
+    prefix="@VALGRIND@ --vgdb=no --leak-check=full --error-exitcode=119 --suppressions=$s/valgrind-suppressions --trace-children=no --child-silent-after-fork=yes --run-libc-freeres=no"
+elif [ "$NBDKIT_GDB" ]; then
+    prefix="gdb --args"
 fi

 # Run the final command.
-exec $valgrind $b/src/nbdkit "${args[@]}"
+exec $prefix $b/src/nbdkit "${args[@]}"
-- 
2.13.6