cmd/dist: Make verbose messages print to stderr

Made the following changes:
 - Export errprintf() from all three OS-specific modules
 - Added errprintf() to a.h
 - Moved errprintf() in windows.c under xprintf(), since they are so similar
 - Replaced all instances of xprintf() with errprintf() where a vflag check is done
Fixes #3788.

R=golang-dev, alex.brainman
CC=golang-dev
https://golang.org/cl/6346056

src/cmd/dist/a.h

@@ -108,6 +108,7 @@ void	xmain(int argc, char **argv);
 
 // portability layer (plan9.c, unix.c, windows.c)
 bool	contains(char *p, char *sep);
+void	errprintf(char*, ...);
 void	fatal(char *msg, ...);
 bool	hasprefix(char *p, char *prefix);
 bool	hassuffix(char *p, char *suffix);

src/cmd/dist/build.c

@@ -147,7 +147,7 @@ static void
 rmworkdir(void)
 {
 	if(vflag > 1)
-		xprintf("rm -rf %s\n", workdir);
+		errprintf("rm -rf %s\n", workdir);
 	xremoveall(workdir);
 }
 
@@ -543,9 +543,9 @@ install(char *dir)
 
 	if(vflag) {
 		if(!streq(goos, gohostos) || !streq(goarch, gohostarch))
-			xprintf("%s (%s/%s)\n", dir, goos, goarch);
+			errprintf("%s (%s/%s)\n", dir, goos, goarch);
 		else
-			xprintf("%s\n", dir);
+			errprintf("%s\n", dir);
 	}
 
 	binit(&b);
@@ -575,7 +575,7 @@ install(char *dir)
 	// For release, cmd/prof and cmd/cov are not included.
 	if((streq(dir, "cmd/cov") || streq(dir, "cmd/prof")) && !isdir(bstr(&path))) {
 		if(vflag > 1)
-			xprintf("skipping %s - does not exist\n", dir);
+			errprintf("skipping %s - does not exist\n", dir);
 		goto out;
 	}
 
@@ -784,7 +784,7 @@ install(char *dir)
 		for(j=0; j<nelem(gentab); j++) {
 			if(hasprefix(elem, gentab[j].nameprefix)) {
 				if(vflag > 1)
-					xprintf("generate %s\n", p);
+					errprintf("generate %s\n", p);
 				gentab[j].gen(bstr(&path), p);
 				// Do not add generated file to clean list.
 				// In pkg/runtime, we want to be able to
@@ -829,7 +829,7 @@ install(char *dir)
 	if((!streq(goos, gohostos) || !streq(goarch, gohostarch)) && isgo) {
 		// We've generated the right files; the go command can do the build.
 		if(vflag > 1)
-			xprintf("skip build for cross-compile %s\n", dir);
+			errprintf("skip build for cross-compile %s\n", dir);
 		goto nobuild;
 	}
 
@@ -1112,7 +1112,7 @@ copy(char *dst, char *src, int exec)
 	Buf b;
 
 	if(vflag > 1)
-		xprintf("cp %s %s\n", src, dst);
+		errprintf("cp %s %s\n", src, dst);
 
 	binit(&b);
 	readfile(&b, src);

src/cmd/dist/plan9.c

@@ -177,7 +177,7 @@ genrun(Buf *b, char *dir, int mode, Vec *argv, int wait)
 		bwritestr(&cmd, q);
 	}
 	if(vflag > 1)
-		xprintf("%s\n", bstr(&cmd));
+		errprintf("%s\n", bstr(&cmd));
 
 	if(b != nil) {
 		breset(b);
@@ -422,7 +422,7 @@ void
 xremove(char *p)
 {
 	if(vflag > 2)
-		xprintf("rm %s\n", p);
+		errprintf("rm %s\n", p);
 	remove(p);
 }
 
@@ -445,7 +445,7 @@ xremoveall(char *p)
 		}
 	}
 	if(vflag > 2)
-		xprintf("rm %s\n", p);
+		errprintf("rm %s\n", p);
 	remove(p);
 	
 	bfree(&b);
@@ -661,6 +661,17 @@ xprintf(char *fmt, ...)
 	va_end(arg);
 }
 
+// errprintf prints a message to standard output.
+void
+errprintf(char *fmt, ...)
+{
+	va_list arg;
+	
+	va_start(arg, fmt);
+	vfprintf(stderr, fmt, arg);
+	va_end(arg);
+}
+
 // xsetenv sets the environment variable $name to the given value.
 void
 xsetenv(char *name, char *value)

src/cmd/dist/unix.c

@@ -177,7 +177,7 @@ genrun(Buf *b, char *dir, int mode, Vec *argv, int wait)
 		bwritestr(&cmd, q);
 	}
 	if(vflag > 1)
-		xprintf("%s\n", bstr(&cmd));
+		errprintf("%s\n", bstr(&cmd));
 
 	if(b != nil) {
 		breset(b);
@@ -398,7 +398,7 @@ void
 xremove(char *p)
 {
 	if(vflag > 2)
-		xprintf("rm %s\n", p);
+		errprintf("rm %s\n", p);
 	unlink(p);
 }
 
@@ -420,11 +420,11 @@ xremoveall(char *p)
 			xremoveall(bstr(&b));
 		}
 		if(vflag > 2)
-			xprintf("rm %s\n", p);
+			errprintf("rm %s\n", p);
 		rmdir(p);
 	} else {
 		if(vflag > 2)
-			xprintf("rm %s\n", p);
+			errprintf("rm %s\n", p);
 		unlink(p);
 	}
 	
@@ -627,6 +627,17 @@ xprintf(char *fmt, ...)
 	va_end(arg);
 }
 
+// errprintf prints a message to standard output.
+void
+errprintf(char *fmt, ...)
+{
+	va_list arg;
+	
+	va_start(arg, fmt);
+	vfprintf(stderr, fmt, arg);
+	va_end(arg);
+}
+
 // xsetenv sets the environment variable $name to the given value.
 void
 xsetenv(char *name, char *value)

src/cmd/dist/windows.c

@@ -121,22 +121,6 @@ errstr(void)
 	return bstr(&b);  // leak but we're dying anyway
 }
 
-static void
-errprintf(char *fmt, ...) {
-	va_list arg;
-	char *p;
-	DWORD n, w;
-
-	va_start(arg, fmt);
-	n = vsnprintf(NULL, 0, fmt, arg);
-	p = xmalloc(n+1);
-	vsnprintf(p, n+1, fmt, arg);
-	va_end(arg);
-	w = 0;
-	WriteFile(GetStdHandle(STD_ERROR_HANDLE), p, n, &w, 0);
-	xfree(p);
-}
-
 void
 xgetenv(Buf *b, char *name)
 {
@@ -332,7 +316,7 @@ genrun(Buf *b, char *dir, int mode, Vec *argv, int wait)
 		}
 	}
 	if(vflag > 1)
-		xprintf("%s\n", bstr(&cmd));
+		errprintf("%s\n", bstr(&cmd));
 
 	torune(&rcmd, bstr(&cmd));
 	rexe = nil;
@@ -547,7 +531,7 @@ readfile(Buf *b, char *file)
 	Rune *r;
 
 	if(vflag > 2)
-		xprintf("read %s\n", file);
+		errprintf("read %s\n", file);
 	torune(&r, file);
 	h = CreateFileW(r, GENERIC_READ, FILE_SHARE_READ|FILE_SHARE_WRITE, nil, OPEN_EXISTING, 0, 0);
 	if(h == INVALID_HANDLE_VALUE)
@@ -566,7 +550,7 @@ writefile(Buf *b, char *file, int exec)
 	USED(exec);
 
 	if(vflag > 2)
-		xprintf("write %s\n", file);
+		errprintf("write %s\n", file);
 	torune(&r, file);
 	h = CreateFileW(r, GENERIC_WRITE, FILE_SHARE_READ|FILE_SHARE_WRITE, nil, CREATE_ALWAYS, 0, 0);
 	if(h == INVALID_HANDLE_VALUE)
@@ -866,6 +850,22 @@ xprintf(char *fmt, ...)
 	xfree(p);
 }
 
+void
+errprintf(char *fmt, ...) {
+	va_list arg;
+	char *p;
+	DWORD n, w;
+
+	va_start(arg, fmt);
+	n = vsnprintf(NULL, 0, fmt, arg);
+	p = xmalloc(n+1);
+	vsnprintf(p, n+1, fmt, arg);
+	va_end(arg);
+	w = 0;
+	WriteFile(GetStdHandle(STD_ERROR_HANDLE), p, n, &w, 0);
+	xfree(p);
+}
+
 int
 main(int argc, char **argv)
 {