Add ARCH to Makefile CFLAGS / LDFLAGS.

This makes builiding with an optional 32 bit target simpler. For
instance Redis (that contains an embedded copy of hiredis) when compiled
with "make 32bit" uses to pass an ARCH parameter to force an hiredis
32 bit build.

Makefile

@@ -15,8 +15,8 @@ CC:=$(shell sh -c 'type $(CC) >/dev/null 2>/dev/null && echo $(CC) || echo gcc')
 OPTIMIZATION?=-O3
 WARNINGS=-Wall -W -Wstrict-prototypes -Wwrite-strings
 DEBUG?= -g -ggdb
-REAL_CFLAGS=$(OPTIMIZATION) -fPIC $(CFLAGS) $(WARNINGS) $(DEBUG)
-REAL_LDFLAGS=$(LDFLAGS)
+REAL_CFLAGS=$(OPTIMIZATION) -fPIC $(CFLAGS) $(WARNINGS) $(DEBUG) $(ARCH)
+REAL_LDFLAGS=$(LDFLAGS) $(ARCH)
 
 DYLIBSUFFIX=so
 STLIBSUFFIX=a