Moved the use of --combine to CFLAGS, we need it for debugging too

Rules.mak

@@ -260,19 +260,6 @@ OPTIMIZATION+=$(call check_gcc,-Os,-O2)
 # Use the gcc 3.4 -funit-at-a-time optimization when available
 OPTIMIZATION+=$(call check_gcc,-funit-at-a-time,)
 
-# we try to compile all sources at once into an object (IMA), but
-# gcc-3.3.x does not support it
-# gcc-3.4.x supports it, but does not need and support --combine
-# gcc-4.0.x supports it, supports the --combine flag, but does not need it
-# gcc-4.1(200506xx) supports it, but needs the --combine flag, else libs are useless
-GCC_VER?=$(shell $(CC) -dumpversion | cut -d . -f 1,2)
-ifeq ($(GCC_VER),3.3)
-# not supported
-DOMULTI=n
-else
-OPTIMIZATION+=$(call check_gcc,--combine,)
-endif
-
 # Add a bunch of extra pedantic annoyingly strict checks
 XWARNINGS=$(subst ",, $(strip $(WARNINGS))) -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing
 XARCH_CFLAGS=$(subst ",, $(strip $(ARCH_CFLAGS)))
@@ -316,6 +303,19 @@ else
     LDFLAGS := $(LDFLAGS_NOSTRIP) -s
 endif
 
+# we try to compile all sources at once into an object (IMA), but
+# gcc-3.3.x does not support it
+# gcc-3.4.x supports it, but does not need and support --combine
+# gcc-4.0.x supports it, supports the --combine flag, but does not need it
+# gcc-4.1(200506xx) supports it, but needs the --combine flag, else libs are useless
+GCC_VER?=$(shell $(CC) -dumpversion | cut -d . -f 1,2)
+ifeq ($(GCC_VER),3.3)
+# not supported
+DOMULTI=n
+else
+CFLAGS+=$(call check_gcc,--combine,)
+endif
+
 ifeq ($(UCLIBC_HAS_THREADS),y)
 ifeq ($(UCLIBC_HAS_THREADS_NATIVE),y)
 	PTNAME := nptl