Align libgloss/arm and libc/sys/arm sources: HeapInfo and __heap_limit

Applied changes from commit 8d98f95:

	* arm/crt0.S: Initialise __heap_limit when ARM_RDI_MONITOR is defined.
	* arm/syscalls.c: define __heap_limit global symbol.
	* arm/syscalls.c (_sbrk): Honour __heap_limit.

Applied changes from commit 8d98f95:
	Fixed semihosting for ARM when heapinfo not provided by debugger

libgloss/arm/syscalls.c

@@ -707,15 +707,15 @@ uint __heap_limit = 0xcafedead;
 void * __attribute__((weak))
 _sbrk (ptrdiff_t incr)
 {
-  extern char end asm ("end"); /* Defined by the linker.  */
+  extern char   end asm ("end"); /* Defined by the linker.  */
   static char * heap_end;
-  char * prev_heap_end;
+  char *        prev_heap_end;
 
   if (heap_end == NULL)
     heap_end = & end;
-  
+
   prev_heap_end = heap_end;
-  
+
   if ((heap_end + incr > stack_ptr)
       /* Honour heap limit if it's valid.  */
       || (__heap_limit != 0xcafedead && heap_end + incr > (char *)__heap_limit))
@@ -726,14 +726,14 @@ _sbrk (ptrdiff_t incr)
       extern void abort (void);
 
       _write (1, "_sbrk: Heap and stack collision\n", 32);
-      
+
       abort ();
 #else
       errno = ENOMEM;
       return (void *) -1;
 #endif
     }
-  
+
   heap_end += incr;
 
   return (void *) prev_heap_end;

newlib/libc/sys/arm/crt0.S

@@ -282,6 +282,13 @@
 #endif
 	ldr	r0, .LC0	/*  Point at values read.  */
 
+	/* Set __heap_limit.  */
+	ldr     r1, [r0, #4]
+	cmp     r1, #0
+	beq     .LC33
+	ldr     r2, =__heap_limit
+	str     r1, [r2]
+.LC33:
 	ldr     r1, [r0, #0]
 	cmp     r1, #0
 	bne     .LC32

newlib/libc/sys/arm/syscalls.c

@@ -487,10 +487,13 @@ _getpid (void)
   return (pid_t)1;
 }
 
+/* Heap limit returned from SYS_HEAPINFO Angel semihost call.  */
+uint __heap_limit = 0xcafedead;
+
 void * __attribute__((weak))
 _sbrk (ptrdiff_t incr)
 {
-  extern char   end asm ("end");	/* Defined by the linker.  */
+  extern char   end asm ("end"); /* Defined by the linker.  */
   static char * heap_end;
   char *        prev_heap_end;
 
@@ -499,7 +502,9 @@ _sbrk (ptrdiff_t incr)
 
   prev_heap_end = heap_end;
 
-  if (heap_end + incr > stack_ptr)
+  if ((heap_end + incr > stack_ptr)
+      /* Honour heap limit if it's valid.  */
+      || (__heap_limit != 0xcafedead && heap_end + incr > (char *)__heap_limit))
     {
       /* Some of the libstdc++-v3 tests rely upon detecting
 	 out of memory errors, so do not abort here.  */