usage.c: drop set_error_handle()

The set_error_handle() function was introduced by 3b331e9
(vreportf: report to arbitrary filehandles, 2015-08-11) so
that run-command could send post-fork, pre-exec errors to
the parent's original stderr.

That use went away in 79319b1 (run-command: eliminate
calls to error handling functions in child, 2017-04-19),
which pushes all of the error reporting to the parent.
This leaves no callers of set_error_handle(). As we're not
likely to add any new ones, let's drop it.

Signed-off-by: Jeff King <peff@peff.net>
Acked-by: Brandon Williams <bmwill@google.com>
Reviewed-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: peff

git-compat-util.h

@@ -445,7 +445,6 @@ extern void (*get_error_routine(void))(const char *err, va_list params);
 extern void set_warn_routine(void (*routine)(const char *warn, va_list params));
 extern void (*get_warn_routine(void))(const char *warn, va_list params);
 extern void set_die_is_recursing_routine(int (*routine)(void));
-extern void set_error_handle(FILE *);
 
 extern int starts_with(const char *str, const char *prefix);
 

usage.c

@@ -6,20 +6,17 @@
 #include "git-compat-util.h"
 #include "cache.h"
 
-static FILE *error_handle;
-
 void vreportf(const char *prefix, const char *err, va_list params)
 {
 	char msg[4096];
-	FILE *fh = error_handle ? error_handle : stderr;
 	char *p;
 
 	vsnprintf(msg, sizeof(msg), err, params);
 	for (p = msg; *p; p++) {
 		if (iscntrl(*p) && *p != '\t' && *p != '\n')
 			*p = '?';
 	}
-	fprintf(fh, "%s%s\n", prefix, msg);
+	fprintf(stderr, "%s%s\n", prefix, msg);
 }
 
 static NORETURN void usage_builtin(const char *err, va_list params)
@@ -88,11 +85,6 @@ void set_die_is_recursing_routine(int (*routine)(void))
 	die_is_recursing = routine;
 }
 
-void set_error_handle(FILE *fh)
-{
-	error_handle = fh;
-}
-
 void NORETURN usagef(const char *err, ...)
 {
 	va_list params;