logger/Makefile: Add hardening flags, pass CFLAGS into LDFLAGS

logger/Makefile

@@ -3,8 +3,16 @@ LD = $(CC)
 RM = rm -f
 MKDIR = mkdir -p
 INSTALL = install -c
-CFLAGS = -Wall -W -O2 -fomit-frame-pointer
-LDFLAGS = -s
+# -pie is a linker option. but let's have it in CFLAGS to ensure -fPIE and -pie
+# are ever overridden or not together
+CFLAGS = -Wall -W -O2 -fomit-frame-pointer -fPIE -pie -fstack-protector-strong -D_FORTIFY_SOURCE=2
+# Include CFLAGS into LDFLAGS for two reasons:
+# 1. "For predictable results, you must also specify the same set of options
+#    used for compilation (-fpie, -fPIE, or model suboptions) when you specify
+#    this linker option." (as gcc man page says about "-pie")
+# 2. In case the package only overrides CFLAGS, we want the distro's hardening
+#    or other flags to also propagate to the linker.
+LDFLAGS = -s -Wl,-z,defs -Wl,-z,relro -Wl,-z,now $(CFLAGS)
 
 DESTDIR =
 PREFIX = /usr/local