Partially restore the fuzzer crate's build rules

Right now the stage1/fuzzer crate will build but it's not linked to librustc
because stage1/librustc won't link.

Makefile.in

@@ -47,6 +47,7 @@ endif
 CFG_RUNTIME :=$(call CFG_LIB_NAME,rustrt)
 CFG_RUSTLLVM :=$(call CFG_LIB_NAME,rustllvm)
 CFG_STDLIB :=$(call CFG_LIB_NAME,std)
+CFG_LIBRUSTC :=$(call CFG_LIB_NAME,rustc)
 
 # version-string calculation
 CFG_GIT_DIR := $(CFG_SRC_DIR).git

mk/fuzzer.mk

-# At the moment the fuzzer only exists in stage2.  That's the first
-# stage built by the non-snapshot compiler so it seems a convenient
-# stage to work at.
+# At the moment the fuzzer only exists in stage1.
 
 FUZZER_CRATE := $(S)src/fuzzer/fuzzer.rc
 FUZZER_INPUTS := $(wildcard $(addprefix $(S)src/fuzzer/, *.rs))
 
-stage2/fuzzer.o: $(FUZZER_CRATE) $(FUZZER_INPUTS) $(SREQ1)
-	@$(call E, compile: $@)
-	$(STAGE1) -c -o $@ $<
-
-stage2/fuzzer$(X): stage2/fuzzer.o $(SREQ1)
-	@$(call E, link [gcc]: $@)
-	$(Q)gcc $(CFG_GCCISH_CFLAGS) rt/main.o stage2/glue.o -o $@ $< \
-      -Lstage2 -Lrustllvm -Lrt -lrustrt -lrustllvm -lstd -lm -lrustc
-	@# dsymutil sometimes fails or prints a warning, but the
-	@# program still runs.  Since it simplifies debugging other
-	@# programs, I\'ll live with the noise.
-	-$(Q)$(CFG_DSYMUTIL) $@
+stage1/fuzzer$(X): $(FUZZER_CRATE) $(FUZZER_INPUTS) $(SREQ1)
+	@$(call E, compile_and_link: $@)
+	$(STAGE1) -o $@ $<

mk/stage1.mk

@@ -29,3 +29,8 @@ stage1/%.o: stage1/%.s
 stage1/%$(X): $(COMPILER_CRATE) $(COMPILER_INPUTS) $(SREQ0) stage0/intrinsics.bc
 	@$(call E, compile_and_link: $@)
 	$(STAGE0) -o $@ $<
+
+stage1/lib/$(CFG_LIBRUSTC): $(COMPILER_CRATE) $(COMPILER_INPUTS) $(SREQ1) \
+                            stage1/intrinsics.bc
+	@$(call E, compile_and_link: $@)
+	$(STAGE1) --shared -o $@ $<

src/fuzzer/fuzzer.rc

 // -*- rust -*-
 
 use std;
-use rustc;
 
 mod fuzzer;
 

src/fuzzer/fuzzer.rs

@@ -6,8 +6,6 @@
 import std::io;
 import std::vec;
 
-import rustc::front::ast;
-
 type src_gen = iter() -> str;
 
 iter dir_src_gen(str dir) -> str {