diff mbox series

[v4,2/8] configure.ac: define ICONV_OMITS_BOM if necessary

Message ID f07566c60c4421a5b33ef5c74a9a0a58947e7750.1573094789.git.congdanhqx@gmail.com (mailing list archive)
State New, archived
Headers show
Series Correct internal working and output encoding | expand

Commit Message

Đoàn Trần Công Danh Nov. 7, 2019, 2:56 a.m. UTC 
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 check into configure script to detect this flag automatically.

Signed-off-by: Doan Tran Cong Danh <congdanhqx@gmail.com>
---
 configure.ac | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

Comments

Junio C Hamano Nov. 7, 2019, 6:18 a.m. UTC | #1 
Doan Tran Cong Danh <congdanhqx@gmail.com> writes:

> 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.

Drop the last sentence.  Not having to give the flags is an already
solved problem and the solution is to use config.mak.

> Add a check into configure script to detect this flag automatically.

This is good.  "Makefile supports this knob, configure script was
not aware of it.  Teach configure to do so" flows the thought
perfectly well (and "typing all the time" does not have to come into
picture).

Thanks.
diff mbox series

Patch

diff --git a/configure.ac b/configure.ac
index a43b476402..ecba7e6e51 100644
--- a/configure.ac
+++ b/configure.ac
@@ -844,12 +844,61 @@  AC_MSG_CHECKING([for old iconv()])
 AC_COMPILE_IFELSE([OLDICONVTEST_SRC],
 	[AC_MSG_RESULT([no])],
 	[AC_MSG_RESULT([yes])
+	AC_DEFINE(HAVE_OLD_ICONV, 1)
 	OLD_ICONV=UnfortunatelyYes])
 
 GIT_UNSTASH_FLAGS($ICONVDIR)
 
 GIT_CONF_SUBST([OLD_ICONV])
 
+#
+# Define ICONV_OMITS_BOM if you are on a system which
+# iconv omits bom for utf-{16,32}
+if test -z "$NO_ICONV"; then
+AC_CACHE_CHECK([whether iconv omits bom for utf-16 and utf-32],
+ [ac_cv_iconv_omits_bom],
+[
+old_LIBS="$LIBS"
+if test -n "$NEEDS_LIBICONV"; then
+	LIBS="$LIBS -liconv"
+fi
+
+AC_RUN_IFELSE(
+	[AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT
+	#include <iconv.h>
+	#ifdef HAVE_OLD_ICONV
+	typedef const char *iconv_ibp;
+	#else
+	typedef char *iconv_ibp;
+	#endif
+	],
+	[[
+	int v;
+	iconv_t conv;
+	char in[] = "a"; iconv_ibp pin = in;
+	char out[20] = ""; char *pout = out;
+	size_t isz = sizeof in;
+	size_t osz = sizeof out;
+
+	conv = iconv_open("UTF-16", "UTF-8");
+	iconv(conv, &pin, &isz, &pout, &osz);
+	iconv_close(conv);
+	v = (unsigned char)(out[0]) + (unsigned char)(out[1]);
+	return v != 0xfe + 0xff;
+	]])],
+	[ac_cv_iconv_omits_bom=no],
+	[ac_cv_iconv_omits_bom=yes])
+
+LIBS="$old_LIBS"
+])
+if test "x$ac_cv_iconv_omits_bom" = xyes; then
+	ICONV_OMITS_BOM=Yes
+else
+	ICONV_OMITS_BOM=
+fi
+GIT_CONF_SUBST([ICONV_OMITS_BOM])
+fi
+
 ## Checks for typedefs, structures, and compiler characteristics.
 AC_MSG_NOTICE([CHECKS for typedefs, structures, and compiler characteristics])
 #