Add ESP8266 configs to PlatformIO build

Added various conditional compliations for ESP8266 to stub out
missing functionality.

googletest/include/gtest/internal/gtest-port.h

@@ -1984,6 +1984,22 @@ inline bool IsDir(const StatStruct& st) {
 }
 # endif  // GTEST_OS_WINDOWS_MOBILE
 
+#elif GTEST_OS_ESP8266
+typedef struct stat StatStruct;
+
+inline int FileNo(FILE* file) { return fileno(file); }
+inline int IsATTY(int fd) { return isatty(fd); }
+inline int Stat(const char* path, StatStruct* buf) { 
+  // stat function not implemented on ESP8266
+  return 0; 
+  }
+inline int StrCaseCmp(const char* s1, const char* s2) {
+  return strcasecmp(s1, s2);
+}
+inline char* StrDup(const char* src) { return strdup(src); }
+inline int RmDir(const char* dir) { return rmdir(dir); }
+inline bool IsDir(const StatStruct& st) { return S_ISDIR(st.st_mode); }
+
 #else
 
 typedef struct stat StatStruct;

googletest/src/gtest-filepath.cc

@@ -236,7 +236,7 @@ bool FilePath::DirectoryExists() const {
     result = true;
   }
 #else
-  posix::StatStruct file_stat;
+  posix::StatStruct file_stat = {};
   result = posix::Stat(path.c_str(), &file_stat) == 0 &&
       posix::IsDir(file_stat);
 #endif  // GTEST_OS_WINDOWS_MOBILE
@@ -323,6 +323,9 @@ bool FilePath::CreateFolder() const {
   delete [] unicode;
 #elif GTEST_OS_WINDOWS
   int result = _mkdir(pathname_.c_str());
+#elif GTEST_OS_ESP8266
+  // do nothing
+  int result = 0;
 #else
   int result = mkdir(pathname_.c_str(), 0777);
 #endif  // GTEST_OS_WINDOWS_MOBILE

googletest/src/gtest_main.cc

@@ -30,13 +30,20 @@
 #include <cstdio>
 #include "gtest/gtest.h"
 
-#if defined GTEST_OS_ESP8266 || defined GTEST_OS_ESP32
+#if GTEST_OS_ESP8266 || GTEST_OS_ESP32
+# if GTEST_OS_ESP8266
+extern "C" {
+# endif
 void setup() {
   testing::InitGoogleTest();
 }
 
 void loop() { RUN_ALL_TESTS(); }
 
+# if GTEST_OS_ESP8266
+}
+# endif
+
 #else
 
 GTEST_API_ int main(int argc, char **argv) {