Description: remove -f*-prefix-map options from .ali files
 The -f(file|debug|macro)-prefix-map=OLD=NEW options
 added by revision 256847
 explicitly ask that OLD is never written.
Forwarded: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87972
Author: Nicolas Boulenguez <nicolas@debian.org>

--- a/src/gcc/ada/lib-writ.adb
+++ b/src/gcc/ada/lib-writ.adb
@@ -1222,10 +1222,22 @@ package body Lib.Writ is
       --  Write command argument ('A') lines
 
       for A in 1 .. Compilation_Switches.Last loop
-         Write_Info_Initiate ('A');
-         Write_Info_Char (' ');
-         Write_Info_Str (Compilation_Switches.Table (A).all);
-         Write_Info_Terminate;
+         --  The -f(file|debug|macro)-prefix-map=OLD=NEW options
+         --  explicitly ask that OLD is never written.
+         declare
+            S : String renames Compilation_Switches.Table (A).all;
+         begin
+            if S'Length < 19            --
+              or else (S (S'First .. S'First + 18) /= "-fdebug-prefix-map="
+                   and S (S'First .. S'First + 17) /= "-ffile-prefix-map="
+                   and S (S'First .. S'First + 18) /= "-fmacro-prefix-map=")
+            then
+               Write_Info_Initiate ('A');
+               Write_Info_Char (' ');
+               Write_Info_Str (S);
+               Write_Info_Terminate;
+            end if;
+         end;
       end loop;
 
       --  Output parameters ('P') line
