projects-dir.mk: Resolve JWB_SCRIPT_DIR from JWBDIR

JWB_SCRIPT_DIR bypasses $(JWBDIR) for its scripts candidate, re-assembling
./$(JWBDIR_NAME)/scripts from the bare name. That works, but is redundant
resolution machinery which should be removed per se.

Resolve the scripts directory from $(JWBDIR) instead. Aside from
simplifying, that fixes the resolution when projects-dir.mk is included
from Makefiles other than projects-dir-miminimal.mk, and  complements work
to commit f3f0ef10ca which also aims at allowing to run make from a
bind-mounted dependency closure of repositories.

Signed-off-by: Jan Lindemann <jan@janware.com>

make/projects-dir.mk

@@ -26,7 +26,7 @@ JWBDIR_SEARCH_PATH          ?= $(DEV_PROJECTS_DIR) $(BUILD_TOOLS_PREFIX)/opt/$(F
 JWBDIR                      ?= $(firstword $(wildcard $(addsuffix /$(JWBDIR_NAME),$(JWBDIR_SEARCH_PATH))))
 
 JW_PKG_BINDIR                = $(JWBDIR)/bin
-JWB_SCRIPT_DIR               = $(firstword $(wildcard ./$(JWBDIR_NAME)/scripts $(JW_PKG_BINDIR)) jwb-script-dir-not-found)
+JWB_SCRIPT_DIR               = $(firstword $(wildcard $(JWBDIR)/scripts $(JW_PKG_BINDIR)) jwb-script-dir-not-found)
 JW_PKG_REMOTE_BINDIR         = /opt/jw-pkg/bin
 
 SHELL                        = /bin/bash -o pipefail +H