mm: use macros from compiler.h instead of __attribute__((...))

To increase compiler portability there is <linux/compiler.h> which
provides convenience macros for various gcc constructs.  Eg: __weak for
__attribute__((weak)).  I've replaced all instances of gcc attributes with
the right macro in the memory management (/mm) subsystem.

[akpm@linux-foundation.org: while-we're-there consistency tweaks]
Signed-off-by: Gideon Israel Dsouza <gidisrael@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/sparse.c b/mm/sparse.c
index 38cad8f..d1b48b6 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -5,10 +5,12 @@
 #include <linux/slab.h>
 #include <linux/mmzone.h>
 #include <linux/bootmem.h>
+#include <linux/compiler.h>
 #include <linux/highmem.h>
 #include <linux/export.h>
 #include <linux/spinlock.h>
 #include <linux/vmalloc.h>
+
 #include "internal.h"
 #include <asm/dma.h>
 #include <asm/pgalloc.h>
@@ -461,7 +463,7 @@
 }
 #endif
 
-void __attribute__((weak)) __meminit vmemmap_populate_print_last(void)
+void __weak __meminit vmemmap_populate_print_last(void)
 {
 }