fix mayberelsrcdir after gcc folder name change

Makefile.in

@@ -16,14 +16,14 @@ DEJAGNU_SRCDIR := @with_dejagnu_src@
 
 SIM ?= @WITH_SIM@
 
-ifeq ($(srcdir)/riscv-gcc,$(GCC_SRCDIR))
+ifeq ($(srcdir)/gcc,$(GCC_SRCDIR))
 # We need a relative source dir for the gcc configure, to make msys2 mingw64
 # builds work.  Mayberelsrcdir is relative if a relative path was used to run
 # configure, otherwise absolute, so we have to check.
 mayberelsrcdir := @top_srcdir@
 gccsrcdir := $(shell case $(mayberelsrcdir) in \
-		  ([\\/]* | ?:[\\/]*)  echo $(mayberelsrcdir)/riscv-gcc ;; \
+		  ([\\/]* | ?:[\\/]*)  echo $(mayberelsrcdir)/gcc ;; \
-		  (*)  echo ../$(mayberelsrcdir)/riscv-gcc ;; \
+		  (*)  echo ../$(mayberelsrcdir)/gcc ;; \
 		esac)
 else
 gccsrcdir := $(abspath $(GCC_SRCDIR))