Rename ProcResult stdout and stderr fields

stdout and stderr are macros in musl, which causes build failures
when they are used as field names.  Rename the fields to stdout_str
and stderr_str.

Test: builds
Change-Id: I04770d2d6e82ca8393308ab12a304838a80f0ae5
diff --git a/libs/androidfw/PosixUtils.cpp b/libs/androidfw/PosixUtils.cpp
index 4ec525a..0269128 100644
--- a/libs/androidfw/PosixUtils.cpp
+++ b/libs/androidfw/PosixUtils.cpp
@@ -114,10 +114,10 @@
       std::unique_ptr<ProcResult> result(new ProcResult());
       result->status = status;
       const auto out = ReadFile(stdout[0]);
-      result->stdout = out ? *out : "";
+      result->stdout_str = out ? *out : "";
       close(stdout[0]);
       const auto err = ReadFile(stderr[0]);
-      result->stderr = err ? *err : "";
+      result->stderr_str = err ? *err : "";
       close(stderr[0]);
       return result;
   }
diff --git a/libs/androidfw/include/androidfw/PosixUtils.h b/libs/androidfw/include/androidfw/PosixUtils.h
index 8fc3ee2..bb20847 100644
--- a/libs/androidfw/include/androidfw/PosixUtils.h
+++ b/libs/androidfw/include/androidfw/PosixUtils.h
@@ -23,8 +23,8 @@
 
 struct ProcResult {
   int status;
-  std::string stdout;
-  std::string stderr;
+  std::string stdout_str;
+  std::string stderr_str;
 };
 
 // Fork, exec and wait for an external process. Return nullptr if the process could not be launched,
diff --git a/libs/androidfw/tests/PosixUtils_test.cpp b/libs/androidfw/tests/PosixUtils_test.cpp
index cf97f87..c7b3eba 100644
--- a/libs/androidfw/tests/PosixUtils_test.cpp
+++ b/libs/androidfw/tests/PosixUtils_test.cpp
@@ -30,14 +30,14 @@
   const auto result = ExecuteBinary({"/bin/date", "--help"});
   ASSERT_THAT(result, NotNull());
   ASSERT_EQ(result->status, 0);
-  ASSERT_EQ(result->stdout.find("usage: date "), 0);
+  ASSERT_EQ(result->stdout_str.find("usage: date "), 0);
 }
 
 TEST(PosixUtilsTest, RelativePathToBinary) {
   const auto result = ExecuteBinary({"date", "--help"});
   ASSERT_THAT(result, NotNull());
   ASSERT_EQ(result->status, 0);
-  ASSERT_EQ(result->stdout.find("usage: date "), 0);
+  ASSERT_EQ(result->stdout_str.find("usage: date "), 0);
 }
 
 TEST(PosixUtilsTest, BadParameters) {