Rename gc/gc_impl.c to gc/default.c

Changing the name makes it clear that this is the default GC in Ruby.

.github/workflows/compilers.yml

@@ -263,9 +263,9 @@ jobs:
 
       - name: Build shared GC
         run: >
-          echo "RUBY_GC_LIBRARY=librubygc.gc_impl.so" >> $GITHUB_ENV &&
+          echo "RUBY_GC_LIBRARY=librubygc.default.so" >> $GITHUB_ENV &&
           mkdir ${{ matrix.entry.shared_gc_dir }} &&
-          make shared-gc SHARED_GC=gc_impl
+          make shared-gc SHARED_GC=default
         if: ${{ matrix.entry.shared_gc }}
 
       - name: Add to ext/Setup

common.mk

@@ -7506,7 +7506,7 @@ gc_impl.$(OBJEXT): $(CCAN_DIR)/container_of/container_of.h
 gc_impl.$(OBJEXT): $(CCAN_DIR)/list/list.h
 gc_impl.$(OBJEXT): $(CCAN_DIR)/str/str.h
 gc_impl.$(OBJEXT): $(hdrdir)/ruby/ruby.h
-gc_impl.$(OBJEXT): $(top_srcdir)/gc/gc_impl.c
+gc_impl.$(OBJEXT): $(top_srcdir)/gc/default.c
 gc_impl.$(OBJEXT): $(top_srcdir)/internal/bits.h
 gc_impl.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 gc_impl.$(OBJEXT): $(top_srcdir)/internal/sanitizers.h
@@ -7528,7 +7528,6 @@ gc_impl.$(OBJEXT): {$(VPATH)}darray.h
 gc_impl.$(OBJEXT): {$(VPATH)}debug.h
 gc_impl.$(OBJEXT): {$(VPATH)}debug_counter.h
 gc_impl.$(OBJEXT): {$(VPATH)}defines.h
-gc_impl.$(OBJEXT): {$(VPATH)}gc/gc_impl.c
 gc_impl.$(OBJEXT): {$(VPATH)}intern.h
 gc_impl.$(OBJEXT): {$(VPATH)}internal/abi.h
 gc_impl.$(OBJEXT): {$(VPATH)}internal/anyargs.h

template/Makefile.in

@@ -67,7 +67,7 @@ RUBY_VERSION_NAME = @RUBY_VERSION_NAME@
 UNIVERSAL_ARCHNAMES = @UNIVERSAL_ARCHNAMES@
 BUILTIN_BINARY = @X_BUILTIN_BINARY@
 
-BUILTIN_GC = gc_impl
+BUILTIN_GC = default
 shared_gc_dir = @shared_gc_dir@
 
 TESTUI = console