Fix type comparison issue that is a hard error in GCC 10.

Taken from upstream:

  https://github.com/OpenTTD/grfcodec/commit/bb692b2c723c5e87cc8f89f445928e97594d5b8f

diff --git a/src/command.cpp b/src/command.cpp
index 9aa0e14..1f32cf1 100644
--- a/src/command.cpp
+++ b/src/command.cpp
@@ -300,8 +300,9 @@ bool parse_comment(const string&line){
 		break;
 	case BEAUTIFY:{
 		commandstream>>command_part;
-		uint val=find_command(command_part,beaut),togglebit;
-		if(val!=(uint)-1&&val!=OFF)_commandState.beautifier=true;
+		int val=find_command(command_part,beaut);
+		uint togglebit;
+		if(val!=-1&&val!=OFF)_commandState.beautifier=true;
 		switch(val){
 		case -1:
 			IssueMessage(0,COMMAND_INVALID_ARG,gen[BEAUTIFY].name);
@@ -372,7 +373,7 @@ bool parse_comment(const string&line){
 dotoggle:
 			commandstream>>command_part;
 			val=find_command(command_part,beaut);
-			if(!commandstream||val==(uint)-1){
+			if(!commandstream||val==-1){
 				IssueMessage(0,COMMAND_INVALID_ARG,gen[BEAUTIFY].name);
 				return true;
 			}
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<tr><td><span title='2024-11-11 07:28:34 +0100'>2024-11-11</span></td><td><a href='/guix/commit/gnu/installer/newt/ethernet.scm?id=f7aa7acc22989e7ebd5d2ba7b4814ce57c93c86a'>installer: Remove unused (newt) imports.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/installer/newt/ethernet.scm,
gnu/installer/newt/keymap.scm,
gnu/installer/newt/locale.scm,
gnu/installer/newt/parameters.scm,
gnu/installer/newt/services.scm: Remove (newt).

Change-Id: Ia6624aaf73491024da54b8ffee7358941b187fdf
</span></span></td><td>Janneke Nieuwenhuizen</td></tr>