Treat a prefix of "$SYSROOT" in the same way as "=" when parsing linker search paths.

	PR ld/21251
	* ldfile.c (ldfile_add_library_path): If the path starts with
	$SYSROOT then use the sysroot as the real prefix.
	* ldlang.c (lang_add_input_file): Treat $SYSROOT in the same
	way as =.
	* ldlex.l: Add $SYSROOT as allow prefix for a filename.
	* ld.texinfo (-L): Document that $SYSROOT acts like = when
	prefixing a library search path.
	(INPUT): Likewise.
	* testsuite/ld-scripts/sysroot-prefix.exp: Add $SYSROOT prefix
	tests.

1 files changed, 5 insertions, 0 deletions

diff --git a/ld/ldlex.l b/ld/ldlex.l
index fa9b924..acba1a2 100644
--- a/ld/ldlex.l
+++ b/ld/ldlex.l
@@ -380,6 +380,11 @@ V_IDENTIFIER [*?.$_a-zA-Z\[\]\-\!\^\\]([*?.$_a-zA-Z0-9\[\]\-\!\^\\]|::)*
 				 yylval.name = xstrdup (yytext);
 				  return NAME;
 				}
+<INPUTLIST>"$SYSROOT"{FILENAMECHAR1}{FILENAMECHAR}*	{
+/* Filename to be prefixed by --sysroot or when non-sysrooted, nothing.  */
+				 yylval.name = xstrdup (yytext);
+				  return NAME;
+				}
 <BOTH,INPUTLIST>"-l"{FILENAMECHAR}+ {
 				  yylval.name = xstrdup (yytext + 2);
 				  return LNAME;