toolchain/uclibc: only use make install_headers for 0.9.29+

0.9.28.3 doesn't have install_headers, so use install_dev there.

Got broken by r23561.

toolchain/uClibc/uclibc.mk

@@ -434,7 +434,11 @@ $(UCLIBC_DIR)/.configured: $(LINUX_HEADERS_DIR)/.configured $(UCLIBC_DIR)/.confi
 		DEVEL_PREFIX=/usr/ \
 		RUNTIME_PREFIX=$(TOOL_BUILD_DIR)/uClibc_dev/ \
 		HOSTCC="$(HOSTCC)" \
+ifeq ($(BR2_UCLIBC_VERSION_0_9_28_3),y)
+		headers install_dev
+else
 		headers install_headers
+endif
 	# Install the kernel headers to the first stage gcc include dir
 	# if necessary
 ifeq ($(LINUX_HEADERS_IS_KERNEL),y)