configure.ac: test for iconv_open with #include <iconv.h> #3942
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@stapelberg Do we want to put this in before the release? |
The previously used AC_SEARCH_LIBS uses AC_LANG_CALL, which is discouraged because it intentionally violates the C type system: it has no way of specifying function parameters, so it does not include the required headers to suppress type warnings: https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/html_node/Generating-Sources.html The new code does what AC_SEARCH_LIBS does, but uses AC_LANG_PROGRAM instead of AC_LANG_CALL. It explicitly includes iconv.h and calls iconv_open with the correct number and type of arguments. This fixes compilation on systems where libiconv’s iconv.h is discovered first, but glibc also provides iconv. Previously, this would result in configure discovering glibc’s iconv, and make failing to compile because -liconv wasn’t specified, but iconv.h pulled in libiconv.
Yes please |
Airblader
approved these changes
Feb 16, 2020
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The previously used AC_SEARCH_LIBS uses AC_LANG_CALL, which is discouraged
because it intentionally violates the C type system: it has no way of specifying
function parameters, so it does not include the required headers to suppress
type warnings:
https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/html_node/Generating-Sources.html
The new code does what AC_SEARCH_LIBS does, but uses AC_LANG_PROGRAM instead of
AC_LANG_CALL. It explicitly includes iconv.h and calls iconv_open with the
correct number and type of arguments.
This fixes compilation on systems where libiconv’s iconv.h is discovered first,
but glibc also provides iconv. Previously, this would result in configure
discovering glibc’s iconv, and make failing to compile because -liconv wasn’t
specified, but iconv.h pulled in libiconv.