Read files using <cstdio> for better portability

Refs sass/sassc-ruby#128

src/file.cpp

@@ -13,9 +13,8 @@
 #else
 # include <unistd.h>
 #endif
-#include <iostream>
-#include <fstream>
 #include <cctype>
+#include <cstdio>
 #include <vector>
 #include <algorithm>
 #include <sys/stat.h>
@@ -462,21 +461,27 @@ namespace Sass {
         // just convert from unsigned char*
         char* contents = (char*) pBuffer;
       #else
+        // Read the file using `<cstdio>` instead of `<fstream>` for better portability.
+        // The `<fstream>` header initializes `<locale>` and this buggy in GCC4/5 with static linking.
+        // See:
+        // https://www.spinics.net/lists/gcchelp/msg46851.html
+        // https://github.com/sass/sassc-ruby/issues/128
         struct stat st;
         if (stat(path.c_str(), &st) == -1 || S_ISDIR(st.st_mode)) return 0;
-        std::ifstream file(path.c_str(), std::ios::in | std::ios::binary | std::ios::ate);
-        char* contents = 0;
-        if (file.is_open()) {
-          size_t size = file.tellg();
-          // allocate an extra byte for the null char
-          // and another one for edge-cases in lexer
-          contents = (char*) malloc((size+2)*sizeof(char));
-          file.seekg(0, std::ios::beg);
-          file.read(contents, size);
-          contents[size+0] = '\0';
-          contents[size+1] = '\0';
-          file.close();
+        FILE* fd = std::fopen(path.c_str(), "rb");
+        if (fd == nullptr) return nullptr;
+        const std::size_t size = st.st_size;
+        char* contents = static_cast<char*>(malloc(st.st_size + 2 * sizeof(char)));
+        if (std::fread(static_cast<void*>(contents), 1, size, fd) != size) {
+          free(contents);
+          return nullptr;
         }
+        if (std::fclose(fd) != 0) {
+          free(contents);
+          return nullptr;
+        }
+        contents[size] = '\0';
+        contents[size + 1] = '\0';
       #endif
       std::string extension;
       if (path.length() > 5) {