[newlib-cygwin] Cygwin: Avoid 'Makefile.in seems to ignore the --datarootdir setting' warning

[Jon TURNEY]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=187281b71134a36b938fbc3147e426a4482466e9

commit 187281b71134a36b938fbc3147e426a4482466e9
Author: Jon Turney <jon.turney@dronecode.org.uk>
Date:   Tue Nov 3 14:50:40 2020 +0000

    Cygwin: Avoid 'Makefile.in seems to ignore the --datarootdir setting' warning
    
    Avoid a 'Makefile.in seems to ignore the --datarootdir setting' warning
    when configuring in testsuite directory.

Diff:
---
 winsup/testsuite/Makefile.in | 1 +
 1 file changed, 1 insertion(+)

diff --git a/winsup/testsuite/Makefile.in b/winsup/testsuite/Makefile.in
index 0e7f6ff1e..50319cda4 100644
--- a/winsup/testsuite/Makefile.in
+++ b/winsup/testsuite/Makefile.in
@@ -35,6 +35,7 @@ endif
 else
 tooldir:=$(exec_prefix)/$(target_alias)
 endif
+datarootdir:=@datarootdir@
 datadir:=${DESTDIR}@datadir@
 infodir:=${DESTDIR}@infodir@
 includedir:=${DESTDIR}@includedir@