Make a brk/sbrk emulation.

Mac OS X seems to have some difficulties with brk/sbrk (maybe with the
4MB heap limit), and replace all the allocation logic will be prone to
errors, I'll add a new define and lib to emulate brk/sbrk using more
standard allocation methods. By default the heap is 64MB, it should be
enough.

modules/src/sbrk/pmfile

@@ -0,0 +1,20 @@
+-- $Source$
+-- $State$
+
+local d = "modules/src/sbrk/"
+lib_sbrk = file (LIBDIR.."libsbrk.a")
+
+module_sbrk = clibrary {
+	cfile (d.."sbrk_emu.c"),
+	
+	outputs = {"%U%/libsbrk.a"},
+	install = {
+		pm.install(LIBDIR.."libsbrk.a"),
+	}
+}
+
+-- Revision history
+-- $Log$
+-- Revision 1.1  2013/03/27 godzil
+-- First version.
+--

modules/src/sbrk/sbrk_emu.c

@@ -0,0 +1,83 @@
+/*
+ * The Amsterdam Compiler Kit
+ * See the copyright notice in the ACK home directory, in the file "Copyright".
+ */
+/* 
+ * sbrk(), brk() emulation based on calloc() 
+ * Based on version from D A Gwyn
+ * 02-Mar-1990     D A Gwyn 
+ * http://www.linuxmisc.com/10-unix-questions/0875f91c36e18724.htm
+ */
+#include <stdio.h>
+#include <errno.h>                      /* for errno, ENOMEM */
+#if __STDC__
+#include <stdlib.h>                     /* for calloc */
+#else 
+extern char *calloc();
+#endif
+
+/* Allocate 64MB to brk/sbrk should be enough for such application */
+#ifndef HEAP_SIZE                       /* with 32-bit ints, 0x200000 is recommended */
+#define HEAP_SIZE       0x4000000       /* size of simulated heap, in bytes */
+#endif
+#define BRK_OK          0
+#define BRK_ERR         (-1)
+#define SBRK_ERR        ((void *)-1)    /* horrible interface design */
+
+static void *bottom = NULL;             /* bottom of calloc()ed pseudo-heap */
+static void *brkval = NULL;             /* current value of simulated break */
+
+int brk_emu( void *endds )
+{
+	int offset;
+	if ( bottom == NULL )
+	{
+		if ( (bottom = calloc( HEAP_SIZE, 1 )) == 0 )
+		{
+			return BRK_ERR; /* unable to set up pseudo-heap */
+		}
+		else
+		{
+			brkval = bottom;
+		}
+	}
+
+	if ( (offset = endds - bottom) < 0 || offset > HEAP_SIZE )
+	{
+		errno = ENOMEM;
+		return BRK_ERR; /* attempt to set break out of heap */
+	}
+	else
+	{
+		brkval = endds;
+		return BRK_OK;
+	}
+}
+
+void *sbrk_emu(int incr)
+{
+	int offset;
+	if ( bottom == 0 )
+	{
+		if ( (bottom = (char *)calloc( HEAP_SIZE, 1 )) == 0 )
+		{
+			return SBRK_ERR; /* unable to set up heap */
+		}
+		else
+		{
+			brkval = bottom;
+		}
+	}
+
+	if ( (offset = (brkval - bottom) + incr) < 0 || offset > HEAP_SIZE )
+	{
+		errno = ENOMEM;
+		return SBRK_ERR; /* attempt to set break out of heap */
+	}
+	else
+	{
+		char *oldbrk = brkval;
+		brkval += incr;
+		return oldbrk;
+	}
+}

modules/src/system/break.c

@@ -6,6 +6,7 @@
 
 #include "system.h"
 #include <unistd.h>
+#include <missing_proto.h>
 
 char *sys_break(int incr)
 {