Code refactoring of Emscripten platform support (single-threaded)

* alloc.c (min_bytes_allocd): Test STACK_NOT_SCANNED macro instead
of __EMSCRIPTEN__ (stack size to scan is zero if STACK_NOT_SCANNED).
* include/private/gcconfig.h (ALIGNMENT): Remove duplicate definition
for _EMSCRIPTEN__.
* include/private/gcconfig.h (STACK_NOT_SCANNED): New macro defined
for __EMSCRIPTEN__ target (in addition to  OS_TYPE, CPP_WORDSZ,
ALIGNMENT, DATASTART, DATAEND).
* mach_dep.c (GC_push_regs): Test STACK_NOT_SCANNED macro instead
of __EMSCRIPTEN__ (push nothing if STACK_NOT_SCANNED).
* mark_rts.c (GC_push_roots): Test STACK_NOT_SCANNED macro instead
of __EMSCRIPTEN__ (do not call GC_push_regs_and_stack if
STACK_NOT_SCANNED); mark cold_gc_frame argument as potentially unused.
* misc.c (GC_clear_stack): Test STACK_NOT_SCANNED macro instead
of __EMSCRIPTEN__ (do not clear stack if STACK_NOT_SCANNED).
* misc.c (GC_clear_stack): Reformat code.

1 files changed, 8 insertions, 6 deletions

diff --git a/mach_dep.c b/mach_dep.c
index a882c76d..29e0b8a7 100644
--- a/mach_dep.c
+++ b/mach_dep.c
@@ -103,7 +103,14 @@
 # define HAVE_PUSH_REGS
 #else  /* No asm implementation */
 
-# if defined(M68K) && defined(AMIGA)
+# ifdef STACK_NOT_SCANNED
+    void GC_push_regs(void)
+    {
+      /* empty */
+    }
+#   define HAVE_PUSH_REGS
+
+# elif defined(M68K) && defined(AMIGA)
     /* This function is not static because it could also be             */
     /* erroneously defined in .S file, so this error would be caught    */
     /* by the linker.                                                   */
@@ -181,11 +188,6 @@
       }
 #     define HAVE_PUSH_REGS
 #   endif /* __MWERKS__ */
-# elif defined(EMSCRIPTEN)
-      void GC_push_regs(void)
-      {
-      }
-#     define HAVE_PUSH_REGS
 # endif /* MACOS */
 
 #endif /* !USE_ASM_PUSH_REGS */