use getline() instead of rolling our own

We use it in other places already as well even though it is farly new
addition to the POSIX family with 2008, but rolling our own here is
really something which should be avoided in such a important method.

Git-Dch: Ignore

methods/gpgv.cc

@@ -86,33 +86,12 @@ string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
    FILE *pipein = fdopen(fd[0], "r");
 
    // Loop over the output of apt-key (which really is gnupg), and check the signatures.
-   size_t buffersize = 64;
-   char *buffer = (char *) malloc(buffersize);
-   size_t bufferoff = 0;
+   size_t buffersize = 0;
+   char *buffer = NULL;
    while (1)
    {
-      int c;
-
-      // Read a line.  Sigh.
-      while ((c = getc(pipein)) != EOF && c != '\n')
-      {
-	 if (bufferoff == buffersize)
-	 {
-	    char* newBuffer = (char *) realloc(buffer, buffersize *= 2);
-	    if (newBuffer == NULL)
-	    {
-	       free(buffer);
-	       return "Couldn't allocate a buffer big enough for reading";
-	    }
-	    buffer = newBuffer;
-	 }
-         *(buffer+bufferoff) = c;
-         bufferoff++;
-      }
-      if (bufferoff == 0 && c == EOF)
-         break;
-      *(buffer+bufferoff) = '\0';
-      bufferoff = 0;
+      if (getline(&buffer, &buffersize, pipein) == -1)
+	 break;
       if (Debug == true)
          std::clog << "Read: " << buffer << std::endl;
 
@@ -126,7 +105,7 @@ string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
             std::clog << "Got BADSIG! " << std::endl;
          BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
       }
-      
+
       if (strncmp(buffer, GNUPGNOPUBKEY, sizeof(GNUPGNOPUBKEY)-1) == 0)
       {
          if (Debug == true)