Some builds of GCC produce output on both stdout and stderr when --help
--verbose is used. The 2>&1 redirection caused them to be arbitrarily
interleaved with each other because of stream buffering. Consequently,
grep failed to match the fvisibility= string in the mixed output, even
though the string was present in GCC's standard output.
This led to silently disabling symbol hiding in some builds of curl.
The latest version(s) of the icc compiler no longer accept the extra
space in the -we (warning enable), -wd (warning disable), etc.
Reported-by: Elmira A Semenova
Bug: http://curl.haxx.se/mail/lib-2013-09/0182.html
The compiler test used a variable before it was assigned when it tried
to see how it acts on a mismatching prototype, which could cause a false
positive.
When nothing is told to configure, we should not enforce switching off
debug options with -g0 (or similar). We instead don't use -g at all in
that situaion and therefore allow the user's CFLAGS settings possibly
dictate what to do.
Currently it is unknown if there is any version of clang that
actually supports -Wstrict-aliasing. What is known is that there
are several that don't support it.
configure script now provides conditional definitions for Makefile.am
that result in CURL_HIDDEN_SYMBOLS being defined by resulting makefiles
when appropriate.
Additionally, configure script option for symbol hiding control is now
named --enable-symbol-hiding --disable-symbol-hiding. While still valid,
old option name --enable-hidden-symbols --disable-hidden-symbols will
be deprecated in some future release.
Add CURL_CHECK_COMPILER as a requirement.
Ensure macro does nothing unless GNU_C or CLANG compiler is used.
This should allow usage of this macro in unforeseen placements.
Temporarily, When cross-compiling with gcc 3.0 or later, enable strict aliasing
rules and warnings. Given that cross-compiled targets autobuilds do not run the
Better disable following warnings when cross-compiling with a gcc older
than 3.0, to avoid warnings from third party system headers:
-Wmissing-declarations
-Wmissing-prototypes
-Wunused
-Wshadow
