fix: restore configuration through env variables

build/Makefile

@@ -1,10 +1,21 @@
+# These flags depend on the system and may be overridden
+WASM_CC := clang
+WASM_CFLAGS := --sysroot=/usr/share/wasi-sysroot
+WASM_LDFLAGS := -nostartfiles
+
+# These are project-specific and are expected to be kept intact
+WASM_TARGET := -target wasm32-unknown-wasi
+WASM_EXTRA_CFLAGS := -I include-wasm/ -Wno-logical-op-parentheses -Wno-parentheses -Oz
+WASM_EXTRA_LDFLAGS := -Wl,-z,stack-size=13312,--no-entry,--compress-relocations,--strip-all
+WASM_EXTRA_LDFLAGS += -Wl,--export=__heap_base,--export=parseCJS,--export=sa
+WASM_EXTRA_LDFLAGS += -Wl,--export=e,--export=re,--export=es,--export=ee
+WASM_EXTRA_LDFLAGS += -Wl,--export=rre,--export=ree,--export=res,--export=ru,--export=us,--export=ue
+
 lib/lexer.wasm: include-wasm/cjs-module-lexer.h src/lexer.c
 	@mkdir -p lib
-	clang --sysroot=/usr/share/wasi-sysroot -target wasm32-unknown-wasi src/lexer.c -I include-wasm -o lib/lexer.wasm -nostartfiles \
-	-Wl,-z,stack-size=13312,--no-entry,--compress-relocations,--strip-all,--export=__heap_base,\
-	--export=parseCJS,--export=sa,--export=e,--export=re,--export=es,--export=ee,--export=rre,--export=ree,--export=res,--export=ru,--export=us,--export=ue \
-	-Wno-logical-op-parentheses -Wno-parentheses \
-	-Oz
+	$(WASM_CC) $(WASM_CFLAGS) $(WASM_TARGET) $(WASM_EXTRA_CFLAGS) \
+        src/lexer.c -o lib/lexer.wasm \
+        $(WASM_LDFLAGS) $(WASM_EXTRA_LDFLAGS)
 
 optimize: lib/lexer.wasm
 	${WASM_OPT} -Oz lib/lexer.wasm -o lib/lexer.wasm