Re: [sr #110268] AC_RUN_IFELSE does not execute the test program although it could
Bruno Haible <[email protected]>
| Newsgroups | gmane.comp.sysutils.autoconf.bugs |
|---|---|
| Message-ID | <4647523.mOMlbgENra@omega> |
Hi Paul,
> Thanks for the bug report. I reverted the patch in question, and then updated
> the manual to mention cross-compiling for mingw as an example.
Thanks.
I still feel that this documentation can be improved:
- It currently says that --host "enables cross-compilation", which is
half right and half wrong (it's right regarding host-type-TOOL programs,
and it's wrong regarding AC_RUN_IFELSE).
- It says "For historical reasons, whenever you specify ‘--host’, be sure to
specify ‘--build’ too". This sentence is obsolete. I'm building packages
with --host and without --build for 15+ years, and it works fine.
- To care about the case of the buggy Wine emulator and how to avoid it,
a sentence could be useful.
Here's a proposed doc patch.
0001-doc-More-clarifications-regarding-host-and-build.patch
(text/x-patch, 2.6 KB)
From 0f612d7ff8f3ac4ecbfe81b3935e46a779f40d6b Mon Sep 17 00:00:00 2001 From: Bruno Haible <[email protected]> Date: Wed, 15 Jul 2020 22:34:24 +0200 Subject: [PATCH] doc: More clarifications regarding --host and --build. * doc/autoconf.texi (Specifying Target Triplets): Describe the effects of --host in more detail. Don't recommend to specify --build when specifying --host. Add another example regarding MinGW. --- doc/autoconf.texi | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-) diff --git a/doc/autoconf.texi b/doc/autoconf.texi index 64129db..d514394 100644 --- a/doc/autoconf.texi +++ b/doc/autoconf.texi @@ -21929,21 +21929,36 @@ cross-compilation mode. @item --host=@var{host-type} the type of system on which the package runs. By default it is the -same as the build machine. Specifying a @var{host-type} that differs +same as the build machine. The tools that get used to build and +manipulate binaries will, by default, all be prefixed with +@code{@var{host-type}-}, such as @code{@var{host-type}-gcc}, +@code{@var{host-type}-g++}, @code{@var{host-type}-ar}, and +@code{@var{host-type}-nm}. If the binaries produced by these tools can +be executed by the build system, the configure script will make use of +it in @code{AC_RUN_IFELSE} invocations; otherwise, cross-compilation +mode is enabled. Specifying a @var{host-type} that differs from @var{build-type}, when @var{build-type} was also explicitly -specified, enables cross-compilation mode. +specified, equally enables cross-compilation mode. @item --target=@var{target-type} the type of system for which any compiler tools in the package produce code (rarely needed). By default, it is the same as host. @end table -If you mean to override the result of @command{config.guess}, use -@option{--build}, not @option{--host}, since the latter enables -cross-compilation. For historical reasons, -whenever you specify @option{--host}, -be sure to specify @option{--build} too; this glitch should be fixed in the -future. So, to enter cross-compilation mode, use a command like this +If you mean to override the result of @command{config.guess} but +still produce binaries for the build machine, use @option{--build}, +not @option{--host}. + +So, for example, to produce binaries for 64-bit MinGW, use a command +like this: + +@example +./configure --host=x86_64-w64-mingw64 +@end example + +If your system has the ability to execute MinGW binaries but you don't +want to make use of this feature and instead prefer cross-compilation +guesses, use a command like this: @example ./configure --build=x86_64-pc-linux-gnu --host=x86_64-w64-mingw64 -- 2.7.4