Author: Chris Spiegel <cspiegel@gmail.com>
Taken from: https://sources.debian.org/patches/gargoyle-free/2019.1.1-2/gcc-10.patch/
--- a/garglk/launcher.c
+++ b/garglk/launcher.c
@@ -48,10 +48,10 @@
 #define ID_GLUL (giblorb_make_id('G','L','U','L'))
 
 #define MaxBuffer 1024
-char tmp[MaxBuffer];
-char terp[MaxBuffer];
-char exe[MaxBuffer];
-char flags[MaxBuffer];
+static char tmp[MaxBuffer];
+static char terp[MaxBuffer];
+static char exe[MaxBuffer];
+static char flags[MaxBuffer];
 
 int runblorb(char *path, char *game)
 {
--- a/garglk/launchgtk.c
+++ b/garglk/launchgtk.c
@@ -41,9 +41,9 @@ static const char * AppName = "Gargoyle " VERSION;
 static const char * LaunchingTemplate = "%s/%s";
 static const char * DirSeparator = "/";
 
-char dir[MaxBuffer];
-char buf[MaxBuffer];
-char tmp[MaxBuffer];
+static char dir[MaxBuffer];
+static char buf[MaxBuffer];
+static char tmp[MaxBuffer];
 
 struct filter
 {
--- a/garglk/launchmac.m
+++ b/garglk/launchmac.m
@@ -40,13 +40,13 @@
 static const char * LaunchingTemplate = "%s/%s";
 static const char * DirSeparator = "/";
 
-char dir[MaxBuffer];
-char buf[MaxBuffer];
-char tmp[MaxBuffer];
-char etc[MaxBuffer];
+static char dir[MaxBuffer];
+static char buf[MaxBuffer];
+static char tmp[MaxBuffer];
+static char etc[MaxBuffer];
 
 enum FILEFILTERS { FILTER_SAVE, FILTER_TEXT, FILTER_ALL };
-char *winfilters[] =
+static char *winfilters[] =
 {
     "sav",
     "txt",
--- a/garglk/launchwin.c
+++ b/garglk/launchwin.c
@@ -33,11 +33,11 @@ static const char * AppName = "Gargoyle " VERSION;
 static const char * LaunchingTemplate = "\"%s\\%s.exe\" %s \"%s\"";
 static const char * DirSeparator = "\\";
 
-char dir[MaxBuffer];
-char buf[MaxBuffer];
-char tmp[MaxBuffer];
+static char dir[MaxBuffer];
+static char buf[MaxBuffer];
+static char tmp[MaxBuffer];
 
-char filterlist[] =
+static char filterlist[] =
 "All Games\0*.taf;*.agx;*.d$$;*.acd;*.a3c;*.asl;*.cas;*.ulx;*.hex;*.jacl;*.j2;*.gam;*.t3;*.z?;*.l9;*.sna;*.mag;*.dat;*.saga;*.blb;*.glb;*.zlb;*.blorb;*.gblorb;*.zblorb\0"
 "Adrift Games (*.taf)\0*.taf\0"
 "AdvSys Games (*.dat)\0*.dat\0"
@@ -65,7 +65,7 @@ void winmsg(const char *msg)
     MessageBox(NULL, msg, AppName, MB_ICONERROR);
 }
 
-int urldecode(char *decoded, unsigned int maxlen, const char *encoded)
+static int urldecode(char *decoded, unsigned int maxlen, const char *encoded)
 {
     unsigned int i;
     int convert, ascii;

--- a/terps/alan2/glkio.h
+++ b/terps/alan2/glkio.h
@@ -11,8 +11,8 @@
 
 #include "glk.h"
 
-winid_t glkMainWin;
-winid_t glkStatusWin;
+extern winid_t glkMainWin;
+extern winid_t glkStatusWin;
 
 /* NB: this header must be included in any file which calls printf() */
 
--- a/terps/alan2/main.c
+++ b/terps/alan2/main.c
@@ -43,6 +43,9 @@
 
 /* PUBLIC DATA */
 
+winid_t glkMainWin;
+winid_t glkStatusWin;
+
 /* The Amachine memory */
 Aword *memory;
 static AcdHdr dummyHeader;	/* Dummy to use until memory allocated */
--- a/terps/alan3/glkio.h
+++ b/terps/alan3/glkio.h
@@ -11,8 +11,8 @@
 
 #include "glk.h"
 
-winid_t glkMainWin;
-winid_t glkStatusWin;
+static winid_t glkMainWin;
+static winid_t glkStatusWin;
 
 /* NB: this header must be included in any file which calls printf() */
 
--- a/terps/alan3/output.h
+++ b/terps/alan3/output.h
@@ -22,9 +22,9 @@ extern bool capitalize;
 /* Log file */
 #ifdef HAVE_GLK
 #include "glk.h"
-strid_t logFile;
+extern strid_t logFile;
 #else
-FILE *logFile;
+extern FILE *logFile;
 #endif
 
 
--- a/terps/alan3/term.h
+++ b/terps/alan3/term.h
@@ -10,7 +10,7 @@
 
 
 /* DATA */
-bool onStatusLine;
+extern bool onStatusLine;
 
 
 /* FUNCTIONS */
--- a/terps/jacl/glk_startup.c
+++ b/terps/jacl/glk_startup.c
@@ -31,7 +31,7 @@ extern short int	release;
 glkunix_startup_t *arguments;
 
 /* THE STREAM FOR OPENING UP THE ARCHIVE CONTAINING GRAPHICS AND SOUND */
-strid_t				blorb_stream;
+extern strid_t				blorb_stream;
 
 /* PROTOTYPE FOR NEEDED UTILITY FUNCTION */
 void create_paths();
--- a/terps/jacl/parser.c
+++ b/terps/jacl/parser.c
@@ -62,7 +62,7 @@ char							*from_word;
 
 int								object_expected = FALSE;
 
-char							default_function[84];
+extern char							default_function[84];
 char							object_name[84];
 
 char				            base_function[84];