8030350: Enable additional compiler warnings for GCC

Reviewed-by: dholmes, coleenp, tbell, erikj, ihse

common/autoconf/generated-configure.sh

@@ -4080,7 +4080,7 @@ pkgadd_help() {
 #CUSTOM_AUTOCONF_INCLUDE
 
 # Do not change or remove the following line, it is needed for consistency checks:
-DATE_WHEN_GENERATED=1392245654
+DATE_WHEN_GENERATED=1392253412
 
 ###############################################################################
 #
@@ -41874,7 +41874,8 @@ fi
   #
   case $COMPILER_NAME in
     gcc )
-      CCXXFLAGS_JDK="$CCXXFLAGS $CCXXFLAGS_JDK -W -Wall -Wno-unused -Wno-parentheses \
+      # these options are used for both C and C++ compiles
+      CCXXFLAGS_JDK="$CCXXFLAGS $CCXXFLAGS_JDK -Wall -Wno-parentheses -Wextra -Wno-unused -Wno-unused-parameter -Wformat=2 \
       -pipe \
       -D_GNU_SOURCE -D_REENTRANT -D_LARGEFILE64_SOURCE"
       case $OPENJDK_TARGET_CPU_ARCH in

common/autoconf/toolchain.m4

@@ -898,7 +898,8 @@ AC_DEFUN_ONCE([TOOLCHAIN_SETUP_COMPILER_FLAGS_FOR_JDK],
   #
   case $COMPILER_NAME in
     gcc )
-      CCXXFLAGS_JDK="$CCXXFLAGS $CCXXFLAGS_JDK -W -Wall -Wno-unused -Wno-parentheses \
+      # these options are used for both C and C++ compiles
+      CCXXFLAGS_JDK="$CCXXFLAGS $CCXXFLAGS_JDK -Wall -Wno-parentheses -Wextra -Wno-unused -Wno-unused-parameter -Wformat=2 \
       -pipe \
       -D_GNU_SOURCE -D_REENTRANT -D_LARGEFILE64_SOURCE"
       case $OPENJDK_TARGET_CPU_ARCH in