tracedump: Don't use color when stdout is not a tty

Previously, if one did an operation like:

	tracedump file.trace > file.dump

The resulting file would be cluttered with escape sequences intending
to change color. Rather than requiring the user to find the --no-color
option, we can simply not use any color escape sequences when stdout
is not a tty.

1 files changed, 1 insertions, 3 deletions

diff --git a/tracedump.cpp b/tracedump.cpp
index c210a0c..77d779d 100644
--- a/tracedump.cpp
+++ b/tracedump.cpp
@@ -34,9 +34,6 @@
 #include "trace_parser.hpp"
 
 
-static bool color = true;
-
-
 static void usage(void) {
     std::cout <<
         "Usage: tracedump [OPTION] [TRACE...]\n"
@@ -51,6 +48,7 @@ static void usage(void) {
 int main(int argc, char **argv)
 {
     int i;
+    bool color = isatty(1);
 
     for (i = 1; i < argc; ++i) {
         const char *arg = argv[i];