+ CFLAGS="-std=c89 -pedantic -Wall -Wextra -Werror $CFLAGS"
+ CFLAGS="-D_XOPEN_SOURCE=500 -Wno-error=int-to-pointer-cast $CFLAGS"
+ # Additional security flags.
+ CFLAGS="$CFLAGS -Wformat -Wformat-security -Werror=format-security"
+ CFLAGS="$CFLAGS -fstack-protector-all -Wstack-protector"
+ CFLAGS="$CFLAGS --param ssp-buffer-size=1"
+ CFLAGS="$CFLAGS -D_FORTIFY_SOURCE=2 -fPIE"
+ LDFLAGS="$LDFLAGS -Wl,-z,relro -Wl,-z,now -fPIE -pie"