Patch BDW GC Bigloo patch with backported Emscripten-related changes from BDW HEAD

gc-patch.patch

--- gc-8.2.2.patch.orig	2023-04-06 11:06:22.632147840 -0700
+++ gc-8.2.2.patch	2023-04-06 11:05:51.015432730 -0700
@@ -189,3 +189,19 @@
  @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/backgraph.Plo@am__quote@ # am--include-marker
  @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/blacklst.Plo@am__quote@ # am--include-marker
  @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/checksums.Plo@am__quote@ # am--include-marker
+diff -Naur gc-8.2.2.orig/include/private/gcconfig.h gc-8.2.2/include/private/gcconfig.h
+--- gc-8.2.2.orig/include/private/gcconfig.h	2022-08-26 11:44:49.000000000 -0700
++++ gc-8.2.2/include/private/gcconfig.h	2023-04-06 11:03:32.704304226 -0700
+@@ -1422,7 +1422,11 @@
+ #     define OS_TYPE "EMSCRIPTEN"
+ #     define DATASTART (ptr_t)ALIGNMENT
+ #     define DATAEND (ptr_t)ALIGNMENT
+-#     define USE_MMAP_ANON      /* avoid /dev/zero, not supported */
++      /* Emscripten does emulate mmap and munmap, but those should  */
++      /* not be used in the collector, since WebAssembly lacks the  */
++      /* native support of memory mapping.  Use sbrk() instead.     */
++#     undef USE_MMAP
++#     undef USE_MUNMAP
+ #     define STACK_GROWS_DOWN
+ #   endif
+ #   if defined(__QNX__)