amend angie build definitions to fix make dist

amend angie build definitions to fix make dist

"make dist" was broken because GNU Make was using a built-in rule
to try to build angie from angie.c . This is a limitation in Automake
when you add a whole subdir with the same name to EXTRA_DIST.
The Automake doc actually discourages adding whole subdirs.

Change-Id: I85ea4ecbd529b060c70f83bcfda7522e1730480d
Signed-off-by: R. Diez <rdiezmail-openocd@yahoo.de>
Reviewed-on: https://review.openocd.org/c/openocd/+/8600
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>