File gdb-fix-incorrect-use-of-is-operator-for-comparison-in-python-lib-gdb-command-prompt.py.patch of Package gdb

Fix incorrect use of 'is' operator for comparison in python/lib/gdb/command/prompt.py

The 'is' operator is not meant to be used for comparisons. It currently working
is an implementation detail of CPython.  CPython 3.8 has added a SyntaxWarning
for this.

---
 gdb/python/lib/gdb/command/prompt.py | 4 ++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/gdb/python/lib/gdb/command/prompt.py b/gdb/python/lib/gdb/command/prompt.py
index 3d662a7d3f..04b9e49c22 100644
--- a/gdb/python/lib/gdb/command/prompt.py
+++ b/gdb/python/lib/gdb/command/prompt.py
@@ -45,7 +45,7 @@ The currently defined substitutions are:
         self.hook_set = False
 
     def get_show_string (self, pvalue):
-        if self.value is not '':
+        if self.value:
            return "The extended prompt is: " + self.value
         else:
            return "The extended prompt is not set."
@@ -57,7 +57,7 @@ The currently defined substitutions are:
         return ""
 
     def before_prompt_hook(self, current):
-        if self.value is not '':
+        if self.value:
             return gdb.prompt.substitute_prompt(self.value)
         else:
             return None