juliac: check whether the configured julia binary supports trimming

juliac/Makefile

@@ -1,9 +1,9 @@
-JULIA ?= /opt/julia/julia-c/bin/julia
+JULIA ?= $(shell which julia)
 JULIAC ?= $(shell $(JULIA) -e 'print(normpath(joinpath(Sys.BINDIR, Base.DATAROOTDIR, "julia", "juliac.jl")))')
 
 RUNIC_FILES := $(wildcard ../src/*.jl) ../Project.toml
 
-runicc: runicc.jl Project.toml Manifest.toml $(RUNIC_FILES)
+runicc: runicc.jl Project.toml Manifest.toml $(RUNIC_FILES) check-julia
 	$(JULIA) --project=. $(JULIAC) --output-exe $@ --trim=unsafe-warn $<
 
 Manifest.toml: Project.toml ../Project.toml
@@ -13,7 +13,15 @@ Manifest.toml: Project.toml ../Project.toml
 clean:
 	-rm -f runicc Manifest.toml
 
+check-julia:
+	@if ! $(JULIA) --help-hidden | grep -s -q '\-\-trim'; then \
+		echo "ERROR: The configured julia binary ($(JULIA)) does not support the --trim argument."; \
+		echo "       Configure the binary using the JULIA variable (e.g. \`JULIA=/path/to/julia make ...\`)"; \
+		echo "       or change how \`julia\` resolves in \`PATH\`."; \
+		exit 1; \
+	fi
+
 print-%:
 	@echo '$*=$($*)'
 
-.PHONY: clean
+.PHONY: clean check-julia