PATCH: Correct use of regsub in lib/compat.exp

[Mark Mitchell <mark at codesourcery dot com>]

We had this code in lib/compat.exp:

!     regsub "^$srcdir/?" $src1 "" testcase
!     regsub "^$tmpdir/?" $testcase "tmpdir-" testcase

This is unsafe, because "$srcdir" or "$tmpdir" might themselves
contain regular-expression characters.  That situation leads to weird
messages, like:

  couldn't compile regular expression pattern: quantifier operand 

Fixed as follows, applied to the 3.4, 4.0, and mainline branches as
near-obvious, and tested on x86_64-unknown-linux-gnu.

--
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com

2005-05-15  Mark Mitchell  <mark@codesourcery.com>

	* lib/compat.exp (compat-execute): Do not use regsub unsafely.

Index: lib/compat.exp
===================================================================
RCS file: /cvs/gcc/gcc/gcc/testsuite/lib/compat.exp,v
retrieving revision 1.12
diff -c -5 -p -r1.12 compat.exp
*** lib/compat.exp	30 Nov 2004 21:37:14 -0000	1.12
--- lib/compat.exp	15 May 2005 22:54:25 -0000
*************** proc compat-execute { src1 sid use_alt }
*** 277,288 ****
      regsub "sid" "sid_x_alt.o" $sid obj2_alt
      regsub "sid" "sid_y_tst.o" $sid obj3_tst
      regsub "sid" "sid_y_alt.o" $sid obj3_alt
  
      # Get the base name of this test, for use in messages.
!     regsub "^$srcdir/?" $src1 "" testcase
!     regsub "^$tmpdir/?" $testcase "tmpdir-" testcase
      regsub "_main.*" $testcase "" testcase
      # Set up the base name of executable files so they'll be unique.
      regsub -all "\[./\]" $testcase "-" execbase
  
      # If we couldn't rip $srcdir out of `src1' then just do the best we can.
--- 277,298 ----
      regsub "sid" "sid_x_alt.o" $sid obj2_alt
      regsub "sid" "sid_y_tst.o" $sid obj3_tst
      regsub "sid" "sid_y_alt.o" $sid obj3_alt
  
      # Get the base name of this test, for use in messages.
!     set testcase "$src1"
!     # Remove the $srcdir and $tmpdir prefixes from $src1.  (It would
!     # be possible to use "regsub" here, if we were careful to escape
!     # all regular expression characters in $srcdir and $tmpdir, but
!     # that would be more complicated that this approach.) 
!     if {[string first "$srcdir/" "$src1"] == 0} {
! 	set testcase [string range "$src1" [string length "$srcdir/"] end]
!     }
!     if {[string first "$tmpdir/" "$testcase"] == 0} {
! 	set testcase [string range "$testcase" [string length "$tmpdir/"] end]
! 	set testcase "tmpdir-$testcase"
!     }
      regsub "_main.*" $testcase "" testcase
      # Set up the base name of executable files so they'll be unique.
      regsub -all "\[./\]" $testcase "-" execbase
  
      # If we couldn't rip $srcdir out of `src1' then just do the best we can.