fmsg: implement suspend in writer

This removes the requirement to call fmsg.Exit on every exit path, and enables direct use of the "log" package. However, fmsg.BeforeExit is still encouraged when possible to catch exit on suspended output.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/linux/interface.go

@@ -54,7 +54,7 @@ type Paths struct {
 func CopyPaths(os System, v *Paths) {
 	v.SharePath = path.Join(os.TempDir(), "fortify."+strconv.Itoa(os.Geteuid()))
 
-	fmsg.VPrintf("process share directory at %q", v.SharePath)
+	fmsg.Verbosef("process share directory at %q", v.SharePath)
 
 	if r, ok := os.LookupEnv(xdgRuntimeDir); !ok || r == "" || !path.IsAbs(r) {
 		// fall back to path in share since fortify has no hard XDG dependency
@@ -65,5 +65,5 @@ func CopyPaths(os System, v *Paths) {
 		v.RunDirPath = path.Join(v.RuntimePath, "fortify")
 	}
 
-	fmsg.VPrintf("runtime directory at %q", v.RunDirPath)
+	fmsg.Verbosef("runtime directory at %q", v.RunDirPath)
 }