examples/elf: add support for CONFIG_DISABLE_SIGNALS

make the example elf can work with SIGNAL disabled

Signed-off-by: v-tangmeng <[email protected]>

Author: TangMeng12

examples/elf/tests/Makefile

@@ -23,7 +23,12 @@
 include $(APPDIR)/Make.defs
 
 ALL_SUBDIRS = errno hello helloxx longjmp mutex pthread signal task struct
-BUILD_SUBDIRS = errno hello struct signal
+BUILD_SUBDIRS = errno hello struct
+
+ifneq ($(CONFIG_DISABLE_SIGNALS),y)
+ALL_SUBDIRS += signal
+BUILD_SUBDIRS += signal
+endif
 
 ifeq ($(CONFIG_HAVE_CXX),y)
 BUILD_SUBDIRS += helloxx