[RFA PATCH] Enable -Wpointer-sign by default.

[Pedro Alves <palves@redhat.com>]

This enables -Wpointer-sign by default.

I've checked that --enable-targets=all builds fine with the following
as --host, on x86_64 Fedora 17 --build:

x86_64 GNU/Linux
i386 GNU/Linux
i386 MinGW-w64
i386 msdos/djgpp

OK?

gdb/
2013-04-19  Pedro Alves  <palves@redhat.com>

	* configure.ac (build_warnings): Replace -Wno-pointer-sign with
	-Wpointer-sign.
	* configure: Regenerate.

gdb/doc
2013-04-19  Pedro Alves  <palves@redhat.com>

	* gdbint.texinfo (Misc Guidelines) <Compiler Warnings>: Replace
	-Wno-pointer-sign text with text on -Wpointer-sign.
---
 gdb/configure          |    2 +-
 gdb/configure.ac       |    2 +-
 gdb/doc/gdbint.texinfo |   13 ++++++-------
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/gdb/configure b/gdb/configure
index f9d9a17..c8f3f1f 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -12452,7 +12452,7 @@ fi
 # NOTE: If you change this list, remember to update
 # gdb/doc/gdbint.texinfo.
 build_warnings="-Wall -Wdeclaration-after-statement -Wpointer-arith \
--Wformat-nonliteral -Wno-pointer-sign \
+-Wformat-nonliteral -Wpointer-sign \
 -Wno-unused -Wunused-value -Wunused-function \
 -Wno-switch -Wno-char-subscripts -Wmissing-prototypes \
 -Wdeclaration-after-statement -Wempty-body"
diff --git a/gdb/configure.ac b/gdb/configure.ac
index ce6fa7a..884b40e 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -1925,7 +1925,7 @@ fi
 # NOTE: If you change this list, remember to update
 # gdb/doc/gdbint.texinfo.
 build_warnings="-Wall -Wdeclaration-after-statement -Wpointer-arith \
--Wformat-nonliteral -Wno-pointer-sign \
+-Wformat-nonliteral -Wpointer-sign \
 -Wno-unused -Wunused-value -Wunused-function \
 -Wno-switch -Wno-char-subscripts -Wmissing-prototypes \
 -Wdeclaration-after-statement -Wempty-body"
diff --git a/gdb/doc/gdbint.texinfo b/gdb/doc/gdbint.texinfo
index 4a75c26..280a860 100644
--- a/gdb/doc/gdbint.texinfo
+++ b/gdb/doc/gdbint.texinfo
@@ -6339,13 +6339,12 @@ Since @value{GDBN} uses the @code{format printf} attribute on all
 @code{printf} like functions this checks not just @code{printf} calls
 but also calls to functions such as @code{fprintf_unfiltered}.
 
-@item -Wno-pointer-sign
-In version 4.0, GCC began warning about pointer argument passing or
-assignment even when the source and destination differed only in
-signedness.  However, most @value{GDBN} code doesn't distinguish
-carefully between @code{char} and @code{unsigned char}.  In early 2006
-the @value{GDBN} developers decided correcting these warnings wasn't
-worth the time it would take.
+@item -Wpointer-sign
+This helps make sure @value{GDBN} code uses @code{gdb_byte} which is
+really @code{unsigned char} for raw bytes instead of @code{char},
+whose signness is host-dependent.  @sc{gcc} enables this with
+@code{-Wall} since version 4.0.  We enable it explicitly too to be
+decoupled from future @sc{gcc} (or other compiler)'s choices.
 
 @item -Wno-unused-parameter
 Due to the way that @value{GDBN} is implemented many functions have