link with c only when target is bpf (#195)

* link with c only when targer is bpf

* provided a no op definition for C entrypoint during unit tests

Author: majabbour

program/rust/src/lib.rs

@@ -2,11 +2,20 @@
 //to reflect the current status of oracle.h
 mod c_oracle_header;
 
+//do not link with C during unit tests (which are built in native architecture, unlike libpyth.o) 
+#[cfg(target_arch = "bpf")]
 #[link(name = "cpyth")]
 extern "C" {
     fn c_entrypoint(input: *mut u8) -> u64;
 }
 
+//make the C entrypoint a no-op when running cargo test
+#[cfg(not(target_arch = "bpf"))]
+pub extern "C" fn c_entrypoint(input: *mut u8) -> u64{
+    0//SUCCESS value
+}
+
+
 #[no_mangle]
 pub extern "C" fn entrypoint(input: *mut u8) -> u64 {
     let c_ret_val = unsafe{c_entrypoint(input)};

scripts/build-bpf.sh

@@ -43,7 +43,10 @@ cd "${RUST_DIR}"
 cargo install bindgen
 bindgen ./src/bindings.h -o ./src/c_oracle_header.rs
 cargo clean
+cargo test
+cargo clean
 cargo build-bpf
+
 sha256sum ./target/**/*.so
 rm ./target/**/*-keypair.json
 rm -r $PYTH_DIR/target || true
@@ -52,3 +55,5 @@ mv ./target $PYTH_DIR/target
 
 
 
+
+