[PATCH] Use __builtin_ffs instead of libc provided ffs in vm_map.c

[Flavio Cruz]

We already this built in in other places and this will move us closer to
being able to build the kernel without libc.
---
 Makefile.am | 4 ++--
 vm/vm_map.c | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/Makefile.am b/Makefile.am
index 684344e2..33f770f6 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -167,13 +167,13 @@ gnumach_o_LINK = $(LD) $(LDFLAGS) -u _start -r -o $@
 noinst_PROGRAMS += \
        gnumach.o
 
-# This is the list of routines we decide is OK to steal from the C library.
+# This is the list of routines we decide is OK to steal from the C library or 
libgcc.
 clib_routines := htonl htons ntohl ntohs                       \
                 udivdi3 __udivdi3 __udivmoddi4 __umoddi3       \
                 __divdi3 __moddi3                              \
                 __rel_iplt_start __rel_iplt_end                \
                 __rela_iplt_start __rela_iplt_end              \
-                __ffsdi2 ffs                                   \
+                __ffsdi2                                       \
                 _START _start etext _edata end _end # actually ld magic, not 
libc.
 gnumach-undef: gnumach.$(OBJEXT)
        $(NM_V) $(NM) -u $< | sed 's/  *U  *//' | sort -u > $@
diff --git a/vm/vm_map.c b/vm/vm_map.c
index ceeb91ee..4200a239 100644
--- a/vm/vm_map.c
+++ b/vm/vm_map.c
@@ -685,10 +685,10 @@ vm_map_find_entry_anywhere(struct vm_map *map,
        if (((mask + 1) & mask) != 0) {
                /* We have high bits in addition to the low bits */
 
-               int first0 = ffs(~mask);                /* First zero after low 
bits */
+               int first0 = __builtin_ffs(~mask);              /* First zero 
after low bits */
                vm_offset_t lowmask = (1UL << (first0-1)) - 1;          /* low 
bits */
                vm_offset_t himask = mask - lowmask;                    /* high 
bits */
-               int second1 = ffs(himask);              /* First one after low 
bits */
+               int second1 = __builtin_ffs(himask);            /* First one 
after low bits */
 
                max = 1UL << (second1-1);
 
-- 
2.37.2