diff -Nru thunderbird-52.6.0/debian/changelog thunderbird-52.6.0/debian/changelog
--- thunderbird-52.6.0/debian/changelog	2018-01-25 19:21:10.000000000 +0000
+++ thunderbird-52.6.0/debian/changelog	2018-02-15 14:01:10.000000000 +0000
@@ -1,3 +1,11 @@
+thunderbird (1:52.6.0-1+rpi1) buster-staging; urgency=medium
+
+  * Build with gcc-5/g++-5. gcc-6 is giving internal compiler errors in raspbian
+    buster (but for some reason not stretch) and gcc-7 apparently causes other 
+    problems ( see debian bug 871629 ).
+
+ -- Peter Michael Green <plugwash@raspbian.org>  Thu, 15 Feb 2018 14:01:10 +0000
+
 thunderbird (1:52.6.0-1) unstable; urgency=high
 
   * [97e1cd7] New upstream version 52.6.0
diff -Nru thunderbird-52.6.0/debian/control thunderbird-52.6.0/debian/control
--- thunderbird-52.6.0/debian/control	2018-01-25 19:21:10.000000000 +0000
+++ thunderbird-52.6.0/debian/control	2018-02-15 14:00:54.000000000 +0000
@@ -13,8 +13,8 @@
  dh-exec,
  dpkg (>= 1.16.18~),
  dpkg-dev (>= 1.16.18~),
- gcc-6,
- g++-6,
+ gcc-5,
+ g++-5,
  libasound2-dev [linux-any],
  libatk-adaptor,
  libbz2-dev,
diff -Nru thunderbird-52.6.0/debian/rules thunderbird-52.6.0/debian/rules
--- thunderbird-52.6.0/debian/rules	2018-01-25 19:21:10.000000000 +0000
+++ thunderbird-52.6.0/debian/rules	2018-02-15 14:00:39.000000000 +0000
@@ -40,8 +40,8 @@
 CFLAGS += -fno-delete-null-pointer-checks -fno-schedule-insns2 -fno-lifetime-dse
 CXXFLAGS += -fno-delete-null-pointer-checks -fno-schedule-insns2 -fno-lifetime-dse
 
-export CC=gcc-6
-export CXX=g++-6
+export CC=gcc-5
+export CXX=g++-5
 
 # special CFLAGS for various platforms
 ifeq ($(DEB_BUILD_ARCH),armel)