refactor setting C SDK path code

Author: yogh333

ledger_secure_sdk_sys/build.rs

@@ -187,12 +187,11 @@ impl SDKBuilder<'_> {
         {
             "nanosplus" => Device {
                 name: DeviceName::NanoSPlus,
-                c_sdk: match env::var("LEDGER_SDK_PATH") {
+                c_sdk: match env::var("LEDGER_SDK_PATH")
+                    .or_else(|_| env::var("NANOSP_SDK"))
+                {
                     Ok(path) => PathBuf::from(path),
-                    Err(_) => match env::var("NANOSP_SDK") {
-                        Ok(path) => PathBuf::from(path),
-                        Err(_) => return Err(SDKBuildError::MissingSDKPath),
-                    },
+                    Err(_) => return Err(SDKBuildError::MissingSDKPath),
                 },
                 target: "thumbv8m.main-none-eabi",
                 defines: {
@@ -216,12 +215,11 @@ impl SDKBuilder<'_> {
             },
             "nanox" => Device {
                 name: DeviceName::NanoX,
-                c_sdk: match env::var("LEDGER_SDK_PATH") {
+                c_sdk: match env::var("LEDGER_SDK_PATH")
+                    .or_else(|_| env::var("NANOX_SDK"))
+                {
                     Ok(path) => PathBuf::from(path),
-                    Err(_) => match env::var("NANOX_SDK") {
-                        Ok(path) => PathBuf::from(path),
-                        Err(_) => return Err(SDKBuildError::MissingSDKPath),
-                    },
+                    Err(_) => return Err(SDKBuildError::MissingSDKPath),
                 },
                 target: "thumbv6m-none-eabi",
                 defines: {
@@ -245,12 +243,11 @@ impl SDKBuilder<'_> {
             },
             "stax" => Device {
                 name: DeviceName::Stax,
-                c_sdk: match env::var("LEDGER_SDK_PATH") {
+                c_sdk: match env::var("LEDGER_SDK_PATH")
+                    .or_else(|_| env::var("STAX_SDK"))
+                {
                     Ok(path) => PathBuf::from(path),
-                    Err(_) => match env::var("STAX_SDK") {
-                        Ok(path) => PathBuf::from(path),
-                        Err(_) => return Err(SDKBuildError::MissingSDKPath),
-                    },
+                    Err(_) => return Err(SDKBuildError::MissingSDKPath),
                 },
                 target: "thumbv8m.main-none-eabi",
                 defines: header2define("csdk_stax.h"),
@@ -261,12 +258,11 @@ impl SDKBuilder<'_> {
             },
             "flex" => Device {
                 name: DeviceName::Flex,
-                c_sdk: match env::var("LEDGER_SDK_PATH") {
+                c_sdk: match env::var("LEDGER_SDK_PATH")
+                    .or_else(|_| env::var("FLEX_SDK"))
+                {
                     Ok(path) => PathBuf::from(path),
-                    Err(_) => match env::var("FLEX_SDK") {
-                        Ok(path) => PathBuf::from(path),
-                        Err(_) => return Err(SDKBuildError::MissingSDKPath),
-                    },
+                    Err(_) => return Err(SDKBuildError::MissingSDKPath),
                 },
                 target: "thumbv8m.main-none-eabi",
                 defines: header2define("csdk_flex.h"),