diff --git a/srcpkgs/firefox/template b/srcpkgs/firefox/template
index 76578da1804..674550b06db 100644
--- a/srcpkgs/firefox/template
+++ b/srcpkgs/firefox/template
@@ -1,7 +1,7 @@
 # Template build file for 'firefox'.
 pkgname=firefox
 version=48.0.2
-revision=2
+revision=3
 short_desc="Lightweight gecko-based web browser"
 maintainer="Juan RP <xtraeme@voidlinux.eu>"
 homepage="https://www.mozilla.org/firefox/"
@@ -34,6 +34,15 @@ case "$XBPS_TARGET_MACHINE" in
 	x86_64*) build_options_default+=" rust" ;;
 esac
 
+_gccver=$(gcc --version | awk '/^gcc \(GCC\)/ { print $3 }')
+if [ "${_gccver%%.*}" -gt 5 ]; then
+	# Append CFLAGS and CXXFLAGS to set work around code which gcc6 would
+	# otherwise regard as out-of-specification and allow it to produce a
+	# working program.
+	CFLAGS+=" -fno-delete-null-pointer-checks -fno-lifetime-dse -fno-schedule-insns2"
+	CXXFLAGS+=" -fno-delete-null-pointer-checks -fno-lifetime-dse -fno-schedule-insns2"
+fi
+
 post_extract() {
 	[ ! -d "${wrkdrc}/xbps-build" ] && mkdir -p "${wrksrc}/xbps-build"
 }