Bug#53445: Build with -Wall and fix warnings that it generates

Introduce a MySQL maintainer/developer mode that enables
a set of warning options for the C/C++ compiler. This mode
is intended to help improve the overall quality of the code.

The warning options are:

C_WARNINGS="-Wall -Wextra -Wunused -Wwrite-strings -Werror"
CXX_WARNINGS="$C_WARNINGS -Wno-unused-parameter"

Since -Wall is essentially a moving target, autoconf checks
are not run with warning options enabled, in particualr -Werror.
This decision might be revisited in the future. The patch also
fixes a mistake in the makefiles, where automake CXXFLAGS would
be set to CFLAGS.

config/ac-macros/maintainer.m4:
  Add a set of default compiler flags used when in maintainer mode.
configure.in:
  Hook into the maintainer mode. Disabled by default.

config/ac-macros/maintainer.m4

+#
+# Control aspects of the development environment which are
+# specific to MySQL maintainers and developers.
+#
+AC_DEFUN([MY_MAINTAINER_MODE], [
+  AC_MSG_CHECKING([whether to enable the maintainer-specific development environment])
+  AC_ARG_ENABLE([mysql-maintainer-mode],
+    [AS_HELP_STRING([--enable-mysql-maintainer-mode],
+                    [Enable a MySQL maintainer-specific development environment])],
+    [USE_MYSQL_MAINTAINER_MODE=$enableval],
+    [USE_MYSQL_MAINTAINER_MODE=no])
+  AC_MSG_RESULT([$USE_MYSQL_MAINTAINER_MODE])
+])
+
+# Set warning options required under maintainer mode.
+AC_DEFUN([MY_MAINTAINER_MODE_WARNINGS], [
+  # Setup GCC warning options.
+  AS_IF([test "$GCC" = "yes"], [
+    C_WARNINGS="-Wall -Wextra -Wunused -Wwrite-strings -Werror"
+    CXX_WARNINGS="${C_WARNINGS} -Wno-unused-parameter"
+  ])
+
+  # Test whether the warning options work.
+  # Test C options
+  AS_IF([test -n "$C_WARNINGS"], [
+    save_CFLAGS="$CFLAGS"
+    AC_MSG_CHECKING([whether to use C warning options ${C_WARNINGS}])
+    AC_LANG_PUSH(C)
+    CFLAGS="$CFLAGS ${C_WARNINGS}"
+    AC_LANG_WERROR
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM()], [myac_c_warning_flags=yes],
+                      [myac_c_warning_flags=no])
+    AC_LANG_POP()
+    AC_MSG_RESULT([$myac_c_warning_flags])
+    CFLAGS="$save_CFLAGS"
+  ])
+
+  # Test C++ options
+  AS_IF([test -n "$CXX_WARNINGS"], [
+    save_CXXFLAGS="$CXXFLAGS"
+    AC_MSG_CHECKING([whether to use C++ warning options ${CXX_WARNINGS}])
+    AC_LANG_PUSH(C++)
+    CXXFLAGS="$CXXFLAGS ${CXX_WARNINGS}"
+    AC_LANG_WERROR
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM()], [myac_cxx_warning_flags=yes],
+                      [myac_cxx_warning_flags=no])
+    AC_LANG_POP()
+    AC_MSG_RESULT([$myac_cxx_warning_flags])
+    CXXFLAGS="$save_CXXFLAGS"
+  ])
+
+  # Set compile flag variables.
+  AS_IF([test "$myac_c_warning_flags" = "yes"], [
+    AM_CFLAGS="${AM_CFLAGS} ${C_WARNINGS}"
+    AC_SUBST([AM_CFLAGS])])
+  AS_IF([test "$myac_cxx_warning_flags" = "yes"], [
+    AM_CXXFLAGS="${AM_CXXFLAGS} ${CXX_WARNINGS}"
+    AC_SUBST([AM_CXXFLAGS])])
+])
+
+
+# Set compiler flags required under maintainer mode.
+AC_DEFUN([MY_MAINTAINER_MODE_SETUP], [
+  AS_IF([test "$USE_MYSQL_MAINTAINER_MODE" = "yes"],
+        [MY_MAINTAINER_MODE_WARNINGS])
+])

configure.in

@@ -65,6 +65,7 @@ MYSQL_TCP_PORT_DEFAULT=3306
 MYSQL_UNIX_ADDR_DEFAULT="/tmp/mysql.sock"
 
 dnl Include m4 
+sinclude(config/ac-macros/maintainer.m4)
 sinclude(config/ac-macros/alloca.m4)
 sinclude(config/ac-macros/check_cpu.m4)
 sinclude(config/ac-macros/character_sets.m4)
@@ -102,6 +103,8 @@ AC_SUBST(SHARED_LIB_MAJOR_VERSION)
 AC_SUBST(SHARED_LIB_VERSION)
 AC_SUBST(AVAILABLE_LANGUAGES)
 
+# Whether the maintainer mode should be enabled.
+MY_MAINTAINER_MODE
 
 # Canonicalize the configuration name.
 
@@ -2889,6 +2892,12 @@ do
 done
 AC_SUBST(sql_union_dirs)
 
+#
+# Setup maintainer mode options by the end to not disturb
+# system and other checks.
+#
+MY_MAINTAINER_MODE_SETUP
+
 # Some usefull subst
 AC_SUBST(CC)
 AC_SUBST(GXX)

plugin/daemon_example/Makefile.am

@@ -27,14 +27,14 @@ INCLUDES =              -I$(top_srcdir)/include -I$(top_builddir)/include \
 EXTRA_LTLIBRARIES =	libdaemon_example.la
 pkgplugin_LTLIBRARIES =	@plugin_daemon_example_shared_target@
 libdaemon_example_la_LDFLAGS =	-module -rpath $(pkgplugindir)
-libdaemon_example_la_CXXFLAGS=	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
+libdaemon_example_la_CXXFLAGS=	$(AM_CXXFLAGS) -DMYSQL_DYNAMIC_PLUGIN
 libdaemon_example_la_CFLAGS =	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
 libdaemon_example_la_SOURCES =	daemon_example.cc
 
 
 EXTRA_LIBRARIES =	libdaemon_example.a
 noinst_LIBRARIES =	@plugin_daemon_example_static_target@
-libdaemon_example_a_CXXFLAGS =	$(AM_CFLAGS)
+libdaemon_example_a_CXXFLAGS =	$(AM_CXXFLAGS)
 libdaemon_example_a_CFLAGS =	$(AM_CFLAGS)
 libdaemon_example_a_SOURCES=	daemon_example.cc
 

storage/archive/Makefile.am

@@ -36,14 +36,14 @@ noinst_PROGRAMS	=	archive_test archive_reader
 EXTRA_LTLIBRARIES =	ha_archive.la
 pkgplugin_LTLIBRARIES =	@plugin_archive_shared_target@
 ha_archive_la_LDFLAGS =	-module -rpath $(pkgplugindir)
-ha_archive_la_CXXFLAGS=	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
+ha_archive_la_CXXFLAGS=	$(AM_CXXFLAGS) -DMYSQL_DYNAMIC_PLUGIN
 ha_archive_la_CFLAGS =	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
 ha_archive_la_SOURCES =	ha_archive.cc azio.c
 
 
 EXTRA_LIBRARIES =	libarchive.a
 noinst_LIBRARIES =	@plugin_archive_static_target@
-libarchive_a_CXXFLAGS =	$(AM_CFLAGS)
+libarchive_a_CXXFLAGS =	$(AM_CXXFLAGS)
 libarchive_a_CFLAGS =	$(AM_CFLAGS)
 libarchive_a_SOURCES =	ha_archive.cc azio.c
 

storage/blackhole/Makefile.am

@@ -35,14 +35,14 @@ noinst_HEADERS =	ha_blackhole.h
 EXTRA_LTLIBRARIES =	ha_blackhole.la
 pkgplugin_LTLIBRARIES =	@plugin_blackhole_shared_target@
 ha_blackhole_la_LDFLAGS=-module -rpath $(pkgplugindir)
-ha_blackhole_la_CXXFLAGS=$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
+ha_blackhole_la_CXXFLAGS=$(AM_CXXFLAGS) -DMYSQL_DYNAMIC_PLUGIN
 ha_blackhole_la_CFLAGS=	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
 ha_blackhole_la_SOURCES=ha_blackhole.cc
 
 
 EXTRA_LIBRARIES =	libblackhole.a
 noinst_LIBRARIES =	@plugin_blackhole_static_target@
-libblackhole_a_CXXFLAGS=$(AM_CFLAGS)
+libblackhole_a_CXXFLAGS=$(AM_CXXFLAGS)
 libblackhole_a_CFLAGS =	$(AM_CFLAGS)
 libblackhole_a_SOURCES=	ha_blackhole.cc
 

storage/csv/Makefile.am

@@ -32,12 +32,12 @@ noinst_HEADERS	  =	ha_tina.h transparent_file.h
 EXTRA_LTLIBRARIES =	ha_csv.la
 pkglib_LTLIBRARIES =	@plugin_csv_shared_target@
 ha_csv_la_LDFLAGS =	-module -rpath $(MYSQLLIBdir)
-ha_csv_la_CXXFLAGS =	$(AM_CFLAGS) -DMYSQL_PLUGIN
+ha_csv_la_CXXFLAGS =	$(AM_CXXFLAGS) -DMYSQL_PLUGIN
 ha_csv_la_SOURCES =	transparent_file.cc ha_tina.cc 
 
 EXTRA_LIBRARIES =	libcsv.a
 noinst_LIBRARIES =	@plugin_csv_static_target@
-libcsv_a_CXXFLAGS =	$(AM_CFLAGS)
+libcsv_a_CXXFLAGS =	$(AM_CXXFLAGS)
 libcsv_a_SOURCES =	transparent_file.cc ha_tina.cc
 
 EXTRA_DIST =		CMakeLists.txt plug.in

storage/example/Makefile.am

@@ -35,14 +35,14 @@ noinst_HEADERS =	ha_example.h
 EXTRA_LTLIBRARIES =	ha_example.la
 pkgplugin_LTLIBRARIES =	@plugin_example_shared_target@
 ha_example_la_LDFLAGS =	-module -rpath $(pkgplugindir)
-ha_example_la_CXXFLAGS=	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
+ha_example_la_CXXFLAGS=	$(AM_CXXFLAGS) -DMYSQL_DYNAMIC_PLUGIN
 ha_example_la_CFLAGS =	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
 ha_example_la_SOURCES =	ha_example.cc
 
 
 EXTRA_LIBRARIES =	libexample.a
 noinst_LIBRARIES =	@plugin_example_static_target@
-libexample_a_CXXFLAGS =	$(AM_CFLAGS)
+libexample_a_CXXFLAGS =	$(AM_CXXFLAGS)
 libexample_a_CFLAGS =	$(AM_CFLAGS)
 libexample_a_SOURCES=	ha_example.cc
 

storage/federated/Makefile.am

@@ -35,14 +35,14 @@ noinst_HEADERS =	ha_federated.h
 EXTRA_LTLIBRARIES =	ha_federated.la
 pkgplugin_LTLIBRARIES =	@plugin_federated_shared_target@
 ha_federated_la_LDFLAGS =	-module -rpath $(pkgplugindir)
-ha_federated_la_CXXFLAGS=	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
+ha_federated_la_CXXFLAGS=	$(AM_CXXFLAGS) -DMYSQL_DYNAMIC_PLUGIN
 ha_federated_la_CFLAGS =	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
 ha_federated_la_SOURCES =	ha_federated.cc
 
 
 EXTRA_LIBRARIES =	libfederated.a
 noinst_LIBRARIES =	@plugin_federated_static_target@
-libfederated_a_CXXFLAGS =	$(AM_CFLAGS)
+libfederated_a_CXXFLAGS =	$(AM_CXXFLAGS)
 libfederated_a_CFLAGS =	$(AM_CFLAGS)
 libfederated_a_SOURCES=	ha_federated.cc
 

storage/ibmdb2i/Makefile.am

@@ -34,7 +34,7 @@ EXTRA_LTLIBRARIES =	ha_ibmdb2i.la
 pkgplugin_LTLIBRARIES =	@plugin_ibmdb2i_shared_target@
 ha_ibmdb2i_la_LIBADD =  -liconv
 ha_ibmdb2i_la_LDFLAGS =	-module -rpath $(MYSQLLIBdir)
-ha_ibmdb2i_la_CXXFLAGS=	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
+ha_ibmdb2i_la_CXXFLAGS=	$(AM_CXXFLAGS) -DMYSQL_DYNAMIC_PLUGIN
 ha_ibmdb2i_la_CFLAGS =	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
 ha_ibmdb2i_la_SOURCES =	ha_ibmdb2i.cc db2i_ileBridge.cc db2i_conversion.cc \
 			db2i_blobCollection.cc db2i_file.cc db2i_charsetSupport.cc \
@@ -44,7 +44,7 @@ ha_ibmdb2i_la_SOURCES =	ha_ibmdb2i.cc db2i_ileBridge.cc db2i_conversion.cc \
 
 EXTRA_LIBRARIES =	libibmdb2i.a
 noinst_LIBRARIES =	@plugin_ibmdb2i_static_target@
-libibmdb2i_a_CXXFLAGS =	$(AM_CFLAGS)
+libibmdb2i_a_CXXFLAGS =	$(AM_CXXFLAGS)
 libibmdb2i_a_CFLAGS =	$(AM_CFLAGS)
 libibmdb2i_a_SOURCES=	$(ha_ibmdb2i_la_SOURCES)
 

storage/innobase/Makefile.am

@@ -156,14 +156,14 @@ libinnobase_a_SOURCES=	btr/btr0btr.c btr/btr0cur.c btr/btr0pcur.c	\
 			ut/ut0ut.c ut/ut0vec.c ut/ut0wqueue.c		\
 			handler/ha_innodb.cc
 
-libinnobase_a_CXXFLAGS=	$(AM_CFLAGS)
+libinnobase_a_CXXFLAGS=	$(AM_CXXFLAGS)
 libinnobase_a_CFLAGS=	$(AM_CFLAGS)
 
 EXTRA_LTLIBRARIES=	ha_innodb.la
 pkgplugin_LTLIBRARIES=	@plugin_innobase_shared_target@
 
 ha_innodb_la_LDFLAGS=	-module -rpath $(pkgplugindir)
-ha_innodb_la_CXXFLAGS=	$(AM_CFLAGS) $(INNODB_DYNAMIC_CFLAGS)
+ha_innodb_la_CXXFLAGS=	$(AM_CXXFLAGS) $(INNODB_DYNAMIC_CFLAGS)
 ha_innodb_la_CFLAGS=	$(AM_CFLAGS) $(INNODB_DYNAMIC_CFLAGS)
 ha_innodb_la_SOURCES=	$(libinnobase_a_SOURCES)
 

storage/innodb_plugin/Makefile.am

@@ -325,14 +325,14 @@ libinnobase_a_SOURCES=	\
 			ut/ut0vec.c			\
 			ut/ut0wqueue.c
 
-libinnobase_a_CXXFLAGS=	$(AM_CFLAGS)
+libinnobase_a_CXXFLAGS=	$(AM_CXXFLAGS)
 libinnobase_a_CFLAGS=	$(AM_CFLAGS)
 
 EXTRA_LTLIBRARIES=	ha_innodb_plugin.la
 pkgplugin_LTLIBRARIES=	@plugin_innodb_plugin_shared_target@
 
 ha_innodb_plugin_la_LDFLAGS=	-module -rpath $(pkgplugindir)
-ha_innodb_plugin_la_CXXFLAGS=	$(AM_CFLAGS) $(INNODB_DYNAMIC_CFLAGS)
+ha_innodb_plugin_la_CXXFLAGS=	$(AM_CXXFLAGS) $(INNODB_DYNAMIC_CFLAGS)
 ha_innodb_plugin_la_CFLAGS=	$(AM_CFLAGS) $(INNODB_DYNAMIC_CFLAGS)
 ha_innodb_plugin_la_SOURCES=	$(libinnobase_a_SOURCES)