This flag fixes compilation error in my vm (#303)

Author: guibescos

program/c/makefile

@@ -7,6 +7,6 @@ cpyth-bpf:
 	bash -c "ar rcs target/libcpyth-bpf.a target/**/*.o"
 cpyth-native:
 #   Compile C code to system architecture for use by rust's cargo test
-	gcc -c ./src/oracle/native/upd_aggregate.c -o ./target/cpyth-native.o
+	gcc -c ./src/oracle/native/upd_aggregate.c -o ./target/cpyth-native.o -fPIC
 #   Bundle C code compiled to system architecture for use by rust's cargo test
 	ar rcs target/libcpyth-native.a ./target/cpyth-native.o