linker options for smaller executable size

Makefile.am

@@ -1,4 +1,4 @@
-AM_CFLAGS  = -std=c99 -pedantic -pipe -funsigned-char -Wno-pointer-sign -fno-exceptions -fstack-protector -Wall -Wextra -Wno-unused-parameter -Wno-unused-function -Wno-unused-label -Wpointer-arith -Wformat -Wreturn-type -Wsign-compare -Wmultichar -Wformat-nonliteral -Winit-self -Wuninitialized -Wno-deprecated -Wformat-security -Werror
+AM_CFLAGS  = -std=c99 -pedantic -pipe -funsigned-char -Wno-pointer-sign -fno-exceptions -fstack-protector -Wall -Wextra -Wno-unused-parameter -Wno-unused-function -Wno-unused-label -Wpointer-arith -Wformat -Wreturn-type -Wsign-compare -Wmultichar -Wformat-nonliteral -Winit-self -Wuninitialized -Wno-deprecated -Wformat-security -Werror -ffunction-sections -fdata-sections -Wl,--gc-sections
 AM_LDFLAGS =
 AM_LDADD =