PR4186: cross-architecture probe building

* main.cxx (main): Add 'a:' and 'B:' options.
* session.h (kbuildflags): New place to store -B args.
* testsuite/systemtap.base/cmd_parse.exp: Test them lightly.
* buildrun.cxx (run_make_cmd): Use "--no-print-directory"
  rather than ">/dev/null" in kbuild invocations.  Pass
  '-a' and '-B' flags along.
* hash.cxx (find_script_hash): Add them.
* NEWS, stap.1.in: Mention this.

1 files changed, 9 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index f07acd9f..a7843979 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,14 @@
 * What's new
 
+- It is now possible to cross-compile systemtap scripts for foreign
+  architectures, using the new '-a ARCH' and '-B OPT=VALUE' flags.
+  For example, put arm-linux-gcc etc. into your $PATH, and point
+  systemtap at the target kernel build tree with:
+     stap -a arm -B CROSS_COMPILE=arm-linux- -r /build/tree  [...]
+  The -B option is passed to kbuild make.  -r identifies the already
+  configured/built kernel tree and -a its architecture (kbuild ARCH=...).
+  Systemtap will infer -p4.
+
 - It is now possible to define multiple probe aliases with the same name.
   A probe will expand to all matching aliases.
 	probe foo = bar { }