Change the CFG_STDLIB_DEFAULT macro into a call that picks the correct stage

stageN/rustc depends on either stageN/libstd.so or stage(N-1)/lib/libstd.rlib
so CFG_STDLIB_DEFAULT needs to try harder to get the dependencies right.

Author: brson

Makefile.in

@@ -50,9 +50,9 @@ CFG_STDLIB :=$(call CFG_LIB_NAME,std)
 CFG_LIBRUSTC :=$(call CFG_LIB_NAME,rustc)
 
 ifdef CFG_DISABLE_SHAREDSTD
-  CFG_STDLIB_DEFAULT := lib/libstd.rlib
+  CFG_STDLIB_DEFAULT = $(1)/lib/libstd.rlib
 else
-  CFG_STDLIB_DEFAULT := $(CFG_STDLIB)
+  CFG_STDLIB_DEFAULT = $(2)/$(CFG_STDLIB)
 endif
 
 # version-string calculation
@@ -165,7 +165,7 @@ define SREQ
 ifdef CFG_DISABLE_SHAREDSTD
 SREQ$(1) = stage$(1)/rustc$(X)          \
            stage$(1)/$$(CFG_RUNTIME)     \
-           stage$(1)/$$(CFG_STDLIB_DEFAULT)  \
+           $$(call CFG_STDLIB_DEFAULT,stage$(1),stage$(1)) \
            stage$(1)/$$(CFG_RUSTLLVM)    \
            stage$(1)/lib/glue.o          \
            stage$(1)/lib/main.o          \
@@ -174,7 +174,7 @@ SREQ$(1) = stage$(1)/rustc$(X)          \
 else
 SREQ$(1) = stage$(1)/rustc$(X)          \
            stage$(1)/$$(CFG_RUNTIME)     \
-           stage$(1)/$$(CFG_STDLIB_DEFAULT)  \
+           $$(call CFG_STDLIB_DEFAULT,stage$(1),stage$(1)) \
            stage$(1)/$$(CFG_RUSTLLVM)    \
            stage$(1)/lib/glue.o          \
            stage$(1)/lib/main.o          \

mk/stageN.mk

@@ -50,10 +50,10 @@ stage$(2)/%.o: stage$(2)/%.s
 	@$$(call E, assemble [gcc]: $$@)
 	$$(Q)gcc $$(CFG_GCCISH_CFLAGS) -o $$@ -c $$<
 
-stage$(2)/rustc$$(X): $$(COMPILER_CRATE) $$(COMPILER_INPUTS) \
-                      stage$(2)/$$(CFG_RUNTIME)              \
-                      stage$(1)/$$(CFG_STDLIB_DEFAULT)       \
-                      stage$(2)/$$(CFG_RUSTLLVM)             \
+stage$(2)/rustc$$(X): $$(COMPILER_CRATE) $$(COMPILER_INPUTS)          \
+                      stage$(2)/$$(CFG_RUNTIME)                       \
+                      $$(call CFG_STDLIB_DEFAULT,stage$(1),stage$(2)) \
+                      stage$(2)/$$(CFG_RUSTLLVM)                      \
                       $$(SREQ$(1))
 	@$$(call E, compile_and_link: $$@)
 	$$(STAGE$(1)) -L stage$(2) -o $$@ $$<