Thread (79 messages) 79 messages, 6 authors, 2019-11-11

Re: [PATCH 2/3] configure.ac: define ICONV_OMITS_BOM if necessary

From: Jeff King <hidden>
Date: 2019-10-31 18:11:18

On Thu, Oct 31, 2019 at 04:26:17PM +0700, Doan Tran Cong Danh wrote:
From commit 79444c9294, ("utf8: handle systems that don't write BOM for
UTF-16", 2019-02-12), we're supporting those systems with iconv that
omits BOM with:

    make ICONV_OMITS_BOM=Yes

However, typing the flag all the time is cumbersome and error-prone.

Add a checking into configure script to detect this flag automatically.
I think it's worth adding this to the configure script, but note that
you can also do:

  echo ICONV_OMITS_BOM=Yes >config.mak

and then "make" by itself will do what you want (it's still annoying and
error-prone to realize you have to specify the flag in the first place).
quoted hunk ↗ jump to hunk
diff --git a/configure.ac b/configure.ac
index a43b476402..790b53bbdc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -690,6 +690,28 @@ fi
 
 fi
 
+#
+# Define ICONV_OMITS_BOM if you are on a system which
+# iconv omits bom for utf-{16,32}
+if test -z "$NO_ICONV"; then
+AC_CACHE_CHECK([whether iconv omits bom for utf-16 and utf-32],
+ [ac_cv_iconv_omits_bom],
+[
+if test "x$cross_compiling" = xyes; then
+	AC_MSG_FAILURE([please provide ac_cv_iconv_omits_bom])
+elif test `printf a | iconv -f utf-8 -t utf-16 | wc -c` = 2; then
The ICONV_OMITS_BOM flag is about the libc iconv that Git will be linked
against. But this is checking the iconv tool. For a system that is using
musl across the board, that would work. But it might not always be the
case (in particular, I don't know if people statically link some
binaries against musl; certainly I've seen people do it with dietlibc).

I think we should be test-compiling a small program, similar to the way
OLD_ICONV works (though I guess we may even need to run the result to
see what happens).

-Peff
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