Allow UTF-8 variant of C locale

It behaves same in scanf, but it allows proper handling of unicode
chars.

Author: nijel

src/api/baseapi.cpp

@@ -208,11 +208,11 @@ TessBaseAPI::TessBaseAPI()
       image_height_(0) {
   const char *locale;
   locale = std::setlocale(LC_ALL, nullptr);
-  ASSERT_HOST(!strcmp(locale, "C"));
+  ASSERT_HOST(!strcmp(locale, "C") || !strcmp(locale, "C.UTF-8"));
   locale = std::setlocale(LC_CTYPE, nullptr);
-  ASSERT_HOST(!strcmp(locale, "C"));
+  ASSERT_HOST(!strcmp(locale, "C") || !strcmp(locale, "C.UTF-8"));
   locale = std::setlocale(LC_NUMERIC, nullptr);
-  ASSERT_HOST(!strcmp(locale, "C"));
+  ASSERT_HOST(!strcmp(locale, "C") || !strcmp(locale, "C.UTF-8"));
 }
 
 TessBaseAPI::~TessBaseAPI() {