[glibc/google/grte/v5-2.27/master] Add a Google-only workaround for an ancient mktemp

[glibc/google/grte/v5-2.27/master] Add a Google-only workaround for an ancient mktemp

[Fangrui Song]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=f2d31c80d6f8a54383dc641947361de760b97d24

commit f2d31c80d6f8a54383dc641947361de760b97d24
Author: Stan Shebs <stanshebs@google.com>
Date:   Wed Mar 7 07:46:50 2018 -0800

    Add a Google-only workaround for an ancient mktemp

Diff:
---
 scripts/check-installed-headers.sh | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/scripts/check-installed-headers.sh b/scripts/check-installed-headers.sh
index 3384e1c3e7..e3c52eadf0 100644
--- a/scripts/check-installed-headers.sh
+++ b/scripts/check-installed-headers.sh
@@ -45,12 +45,15 @@ fi
 case "$1" in
     (c)
         lang_modes="$c_modes"
-        cih_test_c=$(mktemp ${TMPDIR-/tmp}/cih_test_XXXXXX.c)
+	# GOOGLE ONLY: Through an unfortunate combination of circumstances,
+	# the mktemp used here may be as old as 6.12 from 2008, which does
+	# not like having an underscore instead of a dot.
+        cih_test_c=$(mktemp ${TMPDIR-/tmp}/cih_test.XXXXXX.c)
         already="$skip_obsolete_type_check"
     ;;
     (c++)
         lang_modes="$cxx_modes"
-        cih_test_c=$(mktemp ${TMPDIR-/tmp}/cih_test_XXXXXX.cc)
+        cih_test_c=$(mktemp ${TMPDIR-/tmp}/cih_test.XXXXXX.cc)
         # The obsolete-type check can be skipped for C++; it is
         # sufficient to do it for C.
         already="*"