[vte] build: Suppress warnings about ignored returned value

[Egmont Koblinger <egmontkob src gnome org>]

commit 624aadb5793dafe4352aa37405c9e4a67bae6c7c
Author: Egmont Koblinger <egmont gmail com>
Date:   Tue Nov 19 14:16:31 2019 +0100

    build: Suppress warnings about ignored returned value

 src/decoder-cat.cc | 3 +++
 src/parser-cat.cc  | 3 +++
 2 files changed, 6 insertions(+)
---
diff --git a/src/decoder-cat.cc b/src/decoder-cat.cc
index 5640c851..7d34fd91 100644
--- a/src/decoder-cat.cc
+++ b/src/decoder-cat.cc
@@ -191,7 +191,10 @@ private:
                 if (m_codepoints || force_lf)
                         m_str.push_back('\n');
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-result"
                 write(STDOUT_FILENO, m_str.data(), m_str.size());
+#pragma GCC diagnostic pop
                 m_str.clear();
         }
 
diff --git a/src/parser-cat.cc b/src/parser-cat.cc
index dbccedab..d0091978 100644
--- a/src/parser-cat.cc
+++ b/src/parser-cat.cc
@@ -359,7 +359,10 @@ private:
         printout() noexcept
         {
                 m_str.push_back('\n');
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-result"
                 write(STDOUT_FILENO, m_str.data(), m_str.size());
+#pragma GCC diagnostic pop
                 m_str.clear();
         }