From 70b6aa848f45bebde46b55045075ea4003be2df8 Mon Sep 17 00:00:00 2001
From: Mitchell Richters <mjr4077au@gmail.com>
Date: Sat, 22 Oct 2022 13:07:13 +1100
Subject: [PATCH] - Clean up the availability detection of `kdialog` and
 `gxmessage` in POSIX sources.

* Both `kdialog` and `gxmessage` are not core components of the KDE or GNOME desktop environments.
* The environment variable `GNOME_DESKTOP_SESSION_ID` has been deprecated for nearly a decade.
* Systems like Steam Deck are shipping with stripped down DEs where these environment variables were set, but without the associated binaries.
---
 .../common/platform/posix/sdl/crashcatcher.c  |  7 +++---
 source/common/platform/posix/sdl/i_system.cpp | 24 ++++++++-----------
 2 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/source/common/platform/posix/sdl/crashcatcher.c b/source/common/platform/posix/sdl/crashcatcher.c
index 698707027..c88e0fe8a 100644
--- a/source/common/platform/posix/sdl/crashcatcher.c
+++ b/source/common/platform/posix/sdl/crashcatcher.c
@@ -15,6 +15,8 @@
 #include <signal.h>
 #endif
 
+int I_FileAvailable(const char* filename);
+
 
 static const char crash_switch[] = "--cc-handle-crash";
 
@@ -363,12 +365,11 @@ static void crash_handler(const char *logfile)
 
 	if(logfile)
 	{
-		const char *str;
 		char buf[512];
 
-		if((str=getenv("KDE_FULL_SESSION")) && strcmp(str, "true") == 0)
+		if(I_FileAvailable("kdialog"))
 			snprintf(buf, sizeof(buf), "kdialog --title \"Very Fatal Error\" --textbox \"%s\" 800 600", logfile);
-		else if((str=getenv("GNOME_DESKTOP_SESSION_ID")) && str[0] != '\0')
+		else if(I_FileAvailable("gxmessage"))
 			snprintf(buf, sizeof(buf), "gxmessage -buttons \"Okay:0\" -geometry 800x600 -title \"Very Fatal Error\" -center -file \"%s\"", logfile);
 		else
 			snprintf(buf, sizeof(buf), "xmessage -buttons \"Okay:0\" -center -file \"%s\"", logfile);
diff --git a/source/common/platform/posix/sdl/i_system.cpp b/source/common/platform/posix/sdl/i_system.cpp
index 8db0f63ce..512a7d62b 100644
--- a/source/common/platform/posix/sdl/i_system.cpp
+++ b/source/common/platform/posix/sdl/i_system.cpp
@@ -85,22 +85,18 @@ void I_SetIWADInfo()
 {
 }
 
-static bool I_KDialogAvailable()
+extern "C" int I_FileAvailable(const char* filename)
 {
-	// Is KDE running?
-	const char* str = getenv("KDE_FULL_SESSION");
-	if (str && strcmp(str, "true") == 0)
+	FString cmd = "which {0} >/dev/null 2>&1";
+	cmd.Substitute("{0}", filename);
+
+	if (FILE* f = popen(cmd.GetChars(), "r"))
 	{
-		// Is kdialog available?
-		FILE* f = popen("which kdialog >/dev/null 2>&1", "r");
-		if (f != NULL)
-		{
-			int status = pclose(f);
-			return WIFEXITED(status) && WEXITSTATUS(status) == 0;
-		}
+		int status = pclose(f);
+		return WIFEXITED(status) && WEXITSTATUS(status) == 0;
 	}
 
-	return false;
+	return 0;
 }
 
 //
@@ -117,7 +113,7 @@ void Unix_I_FatalError(const char* errortext)
 	// Close window or exit fullscreen and release mouse capture
 	SDL_QuitSubSystem(SDL_INIT_VIDEO);
 
-	if(I_KDialogAvailable())
+	if(I_FileAvailable("kdialog"))
 	{
 		FString cmd;
 		cmd << "kdialog --title \"" GAMENAME " " << GetVersionString()
@@ -311,7 +307,7 @@ int I_PickIWad (WadStuff *wads, int numwads, bool showwin, int defaultiwad, int&
 	}
 
 #ifndef __APPLE__
-	if(I_KDialogAvailable())
+	if(I_FileAvailable("kdialog"))
 	{
 		FString cmd("kdialog --title \"" GAMENAME " ");
 		cmd << GetVersionString() << ": Select an IWAD to use\""