need to use gcc mode thumb, to compile glibc, CFLAGS is not enough

mk/build.mk

@@ -122,6 +122,9 @@ POSTCONFIG=		-@\
 		if [ "$$(grep ^ADK_KERNEL_VERSION_ .config|md5sum)" != "$$(grep ^ADK_KERNEL_VERSION_ .config.old|md5sum)" ];then \
 			make kernelclean;\
 		fi; \
+		if [ "$$(grep ^ADK_LINUX_ARM_WITH_THUMB .config|md5sum)" != "$$(grep ^ADK_LINUX_ARM_WITH_THUMB .config.old|md5sum)" ];then \
+			echo "You should make cleantarget, after changing thumb mode";\
+		fi; \
 		if [ $$rebuild -eq 1 ];then \
 			cp .config .config.old;\
 		fi; \

mk/vars.mk

@@ -87,7 +87,7 @@ TARGET_CFLAGS:=		$(TARGET_CFLAGS_ARCH) -fwrapv -fno-ident $(ADK_TARGET_ABI_CFLAG
 TARGET_CFLAGS_LIBC:=	$(TARGET_CFLAGS_ARCH) -fwrapv -fno-ident $(TARGET_OPTIMIZATION)
 else
 TARGET_CFLAGS:=		$(TARGET_CFLAGS_ARCH) -fwrapv -fno-ident -fhonour-copts $(ADK_TARGET_ABI_CFLAGS) $(MODE_FLAGS)
-TARGET_CFLAGS_LIBC:=	$(TARGET_CFLAGS_ARCH) -fwrapv -fno-ident -fhonour-copts $(TARGET_OPTIMIZATION)
+TARGET_CFLAGS_LIBC:=	$(TARGET_CFLAGS_ARCH) -fwrapv -fno-ident -fhonour-copts $(TARGET_OPTIMIZATION) $(MODE_FLAGS)
 endif
 TARGET_CXXFLAGS:=	$(TARGET_CFLAGS_ARCH) -fwrapv -fno-ident $(MODE_FLAGS)
 TARGET_LDFLAGS:=	-L$(STAGING_TARGET_DIR)/lib -L$(STAGING_TARGET_DIR)/usr/lib \

toolchain/gcc/Makefile

@@ -94,7 +94,11 @@ GCC_CONFOPTS+=          --with-arch=armv6 --with-tune=arm1176jzf-s --with-fpu=vf
 endif
 
 ifeq ($(ADK_TARGET_SYSTEM_CUBOX_I),y)
-GCC_CONFOPTS+=          --with-arch=armv7-a --with-tune=cortex-a9 --with-fpu=neon --with-float=hard
+ifeq ($(ADK_LINUX_ARM_WITH_THUMB),y)
+GCC_CONFOPTS+=          --with-arch=armv7-a --with-tune=cortex-a9 --with-fpu=neon --with-float=hard  --with-mode=thumb
+else
+GCC_CONFOPTS+=          --with-arch=armv7-a --with-tune=cortex-a9 --with-fpu=neon --with-float=hard  --with-mode=arm
+endif
 endif
 
 ifneq ($(ADK_TARGET_ABI),)