Fix latent quote char bug in generic_printstr

generic_printstr prints an empty string like:

      fputs_filtered ("\"\"", stream);

However, this seems wrong to me if the quote character is something
other than double quote.  This patch fixes this latent bug.  Thanks to
Andrew for the test case.

Co-authored-by: Andrew Burgess <aburgess@redhat.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.fortran/empty-string.f90 b/gdb/testsuite/gdb.fortran/empty-string.f90
new file mode 100644
index 0000000..574ed7f
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/empty-string.f90
@@ -0,0 +1,30 @@
+! Copyright 2022 Free Software Foundation, Inc.
+!
+! This program is free software; you can redistribute it and/or modify
+! it under the terms of the GNU General Public License as published by
+! the Free Software Foundation; either version 3 of the License, or
+! (at your option) any later version.
+!
+! This program is distributed in the hope that it will be useful,
+! but WITHOUT ANY WARRANTY; without even the implied warranty of
+! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+! GNU General Public License for more details.
+!
+! You should have received a copy of the GNU General Public License
+! along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+program empty_string
+  implicit none
+
+  integer :: ret
+
+  ret = string_length('')
+
+contains
+
+  integer(kind=4) function string_length(string)
+    character*(*) :: string
+    string_length = len(string)		! Break here.
+  end function string_length
+
+end program empty_string