diff --git a/srcpkgs/ddd/patches/gcc9-ftbfs.patch b/srcpkgs/ddd/patches/gcc9-ftbfs.patch
new file mode 100644
index 0000000000..e369269e53
--- /dev/null
+++ b/srcpkgs/ddd/patches/gcc9-ftbfs.patch
@@ -0,0 +1,101 @@
+From: Sophie Brun <sophie@offensive-security.com>
+Date: Mon, 30 Sep 2019 16:17:19 +0200
+Subject: Fix ftbfs with GCC-9
+
+Last-Update: 2019-10-01
+Description:
+"If a friend declaration specifies a default, it must be a friend
+function definition, and no other declarations of this function are
+allowed in the translation unit."
+Remove default values from declaration and change these functions calls
+in the code to add default values if not overwritten.
+---
+ ddd/DispValue.C |  4 ++--
+ ddd/complete.C  |  2 +-
+ ddd/exit.C      |  2 +-
+ ddd/strclass.C  |  1 +
+ ddd/strclass.h  | 10 ++++++----
+ 5 files changed, 11 insertions(+), 8 deletions(-)
+
+diff --git a/ddd/DispValue.C b/ddd/DispValue.C
+index de25768..2656242 100644
+--- ddd/DispValue.C
++++ ddd/DispValue.C
+@@ -1432,8 +1432,8 @@ void DispValue::get_index_surroundings(string& prefix, string& suffix) const
+ 
+     for (int i = 1; i < nchildren(); i++)
+     {
+-	prefix = common_prefix(prefix, child(i)->full_name());
+-	suffix = common_suffix(suffix, child(i)->full_name());
++	prefix = common_prefix(prefix, child(i)->full_name(), 0);
++	suffix = common_suffix(suffix, child(i)->full_name(), -1);
+     }
+ }
+ 
+diff --git a/ddd/complete.C b/ddd/complete.C
+index b161e74..4bde5ff 100644
+--- ddd/complete.C
++++ ddd/complete.C
+@@ -354,7 +354,7 @@ static void complete_reply(const string& complete_answer, void *qu_data)
+ 	string common_pfx = completions[0];
+ 	int i;
+ 	for (i = 1; i < completions_size; i++)
+-	    common_pfx = common_prefix(common_pfx, completions[i]);
++	    common_pfx = common_prefix(common_pfx, completions[i], 0);
+ 
+ 	if (completions_size > 1 && input == common_pfx)
+ 	{
+diff --git a/ddd/exit.C b/ddd/exit.C
+index f490c23..664f203 100644
+--- ddd/exit.C
++++ ddd/exit.C
+@@ -478,7 +478,7 @@ void get_core_pattern(int signal)
+ 	str_func_ret = "core";
+     }
+     else {
+-	readline(patternfile, pattern);
++	readline(patternfile, pattern, '\n', 1);
+ 	core_pat = pattern.chars();
+ 	while(*core_pat)
+ 	{
+diff --git a/ddd/strclass.C b/ddd/strclass.C
+index be0bade..dfbb054 100644
+--- ddd/strclass.C
++++ ddd/strclass.C
+@@ -1563,6 +1563,7 @@ std::istream& operator>>(std::istream& s, string& x)
+     return s;
+ }
+ 
++
+ int readline(std::istream& s, string& x, char terminator, int discard)
+ {
+     assert(!x.consuming());
+diff --git a/ddd/strclass.h b/ddd/strclass.h
+index 7ef16fa..035a17e 100644
+--- ddd/strclass.h
++++ ddd/strclass.h
+@@ -811,9 +811,11 @@ public:
+ 		     const regex& sep);
+ 
+     friend string common_prefix(const string& x, const string& y, 
+-				int startpos = 0);
++				int startpos);
++
+     friend string common_suffix(const string& x, const string& y, 
+-				int startpos = -1);
++				int startpos);
++
+     friend string replicate(char c, int n);
+     friend string replicate(const string& y, int n);
+     friend string join(const string *src, int n, const string& sep);
+@@ -864,8 +866,8 @@ public:
+     friend std::istream& operator>>(std::istream& s, string& x);
+ 
+     friend int readline(std::istream& s, string& x, 
+-			char terminator = '\n',
+-			int discard_terminator = 1);
++			char terminator,
++			int discard_terminator);
+ 
+     // Status
+     unsigned int length() const;