libstdc++ testsuite failure on AIX

[David Edelsohn]

	The libstdc++ testsuite now fails to run on AIX with the following
error in the log file:

ERROR: tcl error sourcing /farm/dje/src/src/libstdc++-v3/testsuite/libstdc++-dg/normal.exp.
ERROR: could not compile testsuite_abi.cc
    while executing
"error "could not compile $f""
    (procedure "v3-build_support" line 33)
    invoked from within
"v3-build_support"
    (file "/farm/dje/src/src/libstdc++-v3/testsuite/libstdc++-dg/normal.exp" line 25)
    invoked from within
"source /farm/dje/src/src/libstdc++-v3/testsuite/libstdc++-dg/normal.exp"
    ("uplevel" body line 1)
    invoked from within
"uplevel #0 source /farm/dje/src/src/libstdc++-v3/testsuite/libstdc++-dg/normal.exp"
    invoked from within
"catch "uplevel #0 source $test_file_name""
testcase /farm/dje/src/src/libstdc++-v3/testsuite/libstdc++-dg/normal.exp completed in 17 seconds