update syntex-0.42.2 to use the new patches scheme

we first build normally, then incrementally (with no saved state), and
finally incrementally again (without changing anything)

Author: nikomatsakis

syntex-0.42.2/makefile

@@ -3,11 +3,22 @@
 # Time how long it takes to build `syntex_syntax`. See
 # `../syntax-0.42.2-incr-clean/makefile` for some further notes.
 
-all:
+all@000-base:
 	cargo rustc -p syntex_syntax $(CARGO_OPTS) -- $(CARGO_RUSTC_OPTS)
+all@010-incr:
+	find . -name '*.rs' | xargs touch
+	RUSTFLAGS="-Z incremental=incr" \
+	    cargo rustc -p syntex_syntax $(CARGO_OPTS) -- \
+	    $(CARGO_RUSTC_OPTS) -Z incremental-info
+all@020-clean:
+	find . -name '*.rs' | xargs touch
+	RUSTFLAGS="-Z incremental=incr" \
+	    cargo rustc -p syntex_syntax $(CARGO_OPTS) -- \
+	    $(CARGO_RUSTC_OPTS) -Z incremental-info
 touch:
-	cargo clean -p syntex_syntax
+	find . -name '*.rs' | xargs touch
+	rm -rf incr
 clean:
 	cargo clean
 patches:
-	@echo ''
+	@echo '@000-base @010-incr @020-clean'