Teach Git how to parse standard power of 2 suffixes.

Sometimes its necessary to supply a value as a power of two in a
configuration parameter.  In this case the user may want to use the
standard suffixes such as K, M, or G to indicate that the numerical
value should be multiplied by a constant base before being used.

Shell scripts/etc. can also benefit from this automatic option
parsing with `git repo-config --int`.

[jc: with a couple of test and a slight input tightening]

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

config.c

@@ -238,6 +238,12 @@ int git_config_int(const char *name, const char *value)
 		int val = strtol(value, &end, 0);
 		if (!*end)
 			return val;
+		if (!strcasecmp(end, "k"))
+			return val * 1024;
+		if (!strcasecmp(end, "m"))
+			return val * 1024 * 1024;
+		if (!strcasecmp(end, "g"))
+			return val * 1024 * 1024 * 1024;
 	}
 	die("bad config value for '%s' in %s", name, config_file_name);
 }