build: build with installed jerbuild (no ~/mine/jerboa dependency)

ober

617403ddb68bcd3ed919c42d95f70d8d58c1aea7

diff --git a/Makefile b/Makefile
index 56ef496..40dfa30 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,10 @@
-JERBOA_HOME ?= $(HOME)/mine/jerboa
-SCHEME      ?= $(JERBOA_HOME)/.chez/bin/scheme
-JERBUILD    ?= $(JERBOA_HOME)/jerbuild
-LIBDIRS      = lib:$(JERBOA_HOME)/lib
+JERBUILD ?= jerbuild
+JH := $(shell $(JERBUILD) --jerboa-home 2>/dev/null)
+ifeq ($(JH),)
+$(error jerbuild not found on PATH (or '$(JERBUILD) --jerboa-home' failed). Install jerbuild, or set JERBUILD=/path/to/jerbuild)
+endif
+
+LIBDIRS      = lib:$(JH)/lib
 
 # Vendor (scintilla-vendor static archives)
 SCINTILLA_VENDOR ?= $(HOME)/mine/scintilla-vendor
@@ -71,7 +74,7 @@ build: transpile shim
 test: build
 	JERBOA_SCINTILLA_LIB=$(CURDIR) \
 	$(LD_VAR)=$(CURDIR) \
-	$(SCHEME) --libdirs "$(LIBDIRS)" --script tests/run-tests.ss
+	$(JERBUILD) exec --libdirs "$(LIBDIRS)" tests/run-tests.ss
 
 clean:
 	rm -f $(SHIM) chez_scintilla_shim.so