diff --git a/srcpkgs/openjdk/files/003_fix-mask_shift.patch b/srcpkgs/openjdk/files/003_fix-mask_shift.patch
new file mode 100644
index 0000000000..21db3fd886
--- /dev/null
+++ b/srcpkgs/openjdk/files/003_fix-mask_shift.patch
@@ -0,0 +1,13 @@
+Use ~0u instead of -1 to shift an unsigned value.
+
+--- a/src/share/vm/code/dependencies.hpp	2016-04-25 18:32:00.000000000 +0200
++++ b/src/share/vm/code/dependencies.hpp	2016-09-13 19:46:22.684595758 +0200
+@@ -166,7 +166,7 @@
+     LG2_TYPE_LIMIT = 4,  // assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT))
+ 
+     // handy categorizations of dependency types:
+-    all_types           = ((1 << TYPE_LIMIT) - 1) & ((-1) << FIRST_TYPE),
++    all_types           = ((1 << TYPE_LIMIT) - 1) & (~0u << FIRST_TYPE),
+ 
+     non_klass_types     = (1 << call_site_target_value),
+     klass_types         = all_types & ~non_klass_types,
diff --git a/srcpkgs/openjdk/template b/srcpkgs/openjdk/template
index f6ccdd6377..5983df8a54 100644
--- a/srcpkgs/openjdk/template
+++ b/srcpkgs/openjdk/template
@@ -129,6 +129,13 @@ alternatives="
 "
 
 CFLAGS="-Wno-error=deprecated-declarations"
+_gccver=$(gcc --version | awk '/^gcc \(GCC\)/ { print $3 }')
+if [ "${_gccver%%.*}" -gt 5 ]; then
+	# Append CFLAGS to set work around code which gcc6 would
+	# otherwise regard as out-of-specification and allow it
+	# to produce a working program.
+	CFLAGS+=" -Wno-error -std=c++98 -fno-delete-null-pointer-checks -fno-lifetime-dse"
+fi
 
 do_build() {
 	# -D_FORTIFY_SOURCE=2 doesn't work with CXX_O_FLAG_NONE="-O0"
@@ -138,6 +145,16 @@ do_build() {
 }
 
 post_extract() {
+	if [ "${_gccver%%.*}" -gt 5 ]; then
+		cd ${XBPS_BUILDDIR}/jdk-${_repo_ver}
+		# gcc6 complains about the signed shift left
+		sed -i src/share/native/com/sun/java/util/jar/pack/constants.h \
+			-e's;(-1)<<13;~0u<<13;g'
+		# wrong "return false;" instead of "return null;"
+		sed -i src/share/native/com/sun/java/util/jar/pack/jni.cpp \
+			-e"295s;false;null;"
+		cd ${wrksrc}
+	fi
 	chmod +x configure
 	for subrepo in corba hotspot jdk jaxws jaxp langtools nashorn; do
 		ln -s ../${subrepo}-${_repo_ver} ${subrepo}