1# warnings.m4 serial 11
2# modified for strace project
3dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
4dnl This file is free software; the Free Software Foundation
5dnl gives unlimited permission to copy and/or distribute it,
6dnl with or without modifications, as long as this notice is preserved.
7
8dnl From Simon Josefsson
9
10# gl_AS_VAR_APPEND(VAR, VALUE)
11# ----------------------------
12# Provide the functionality of AS_VAR_APPEND if Autoconf does not have it.
13m4_ifdef([AS_VAR_APPEND],
14[m4_copy([AS_VAR_APPEND], [gl_AS_VAR_APPEND])],
15[m4_define([gl_AS_VAR_APPEND],
16[AS_VAR_SET([$1], [AS_VAR_GET([$1])$2])])])
17
18
19# gl_COMPILER_OPTION_IF(OPTION, [IF-SUPPORTED], [IF-NOT-SUPPORTED],
20#                       [PROGRAM = AC_LANG_PROGRAM()])
21# -----------------------------------------------------------------
22# Check if the compiler supports OPTION when compiling PROGRAM.
23#
24# FIXME: gl_Warn must be used unquoted until we can assume Autoconf
25# 2.64 or newer.
26AC_DEFUN([gl_COMPILER_OPTION_IF],
27[AS_VAR_PUSHDEF([gl_Flags], _AC_LANG_PREFIX[]FLAGS)dnl
28AS_VAR_PUSHDEF([gl_Warn], [gl_cv_warn_[]gl_Flags[]_$1])dnl
29AS_LITERAL_IF([$1],
30  [m4_pushdef([gl_Positive], m4_bpatsubst([$1], [^-Wno-], [-W]))],
31  [gl_positive="$1"
32case $gl_positive in
33  -Wno-*) gl_positive=-W`expr "X$gl_positive" : 'X-Wno-\(.*\)'` ;;
34esac
35m4_pushdef([gl_Positive], [$gl_positive])])dnl
36AC_CACHE_CHECK([whether $[]_AC_CC[] handles $1], m4_defn([gl_Warn]), [
37  gl_save_compiler_FLAGS="$gl_Flags"
38  gl_AS_VAR_APPEND(m4_defn([gl_Flags]),
39    [" $gl_unknown_warnings_are_errors ]m4_defn([gl_Positive])["])
40  AC_LINK_IFELSE([m4_default([$4], [AC_LANG_PROGRAM([])])],
41                 [AS_VAR_SET(gl_Warn, [yes])],
42                 [AS_VAR_SET(gl_Warn, [no])])
43  gl_Flags="$gl_save_compiler_FLAGS"
44])
45AS_VAR_IF(gl_Warn, [yes], [$2], [$3])
46m4_popdef([gl_Positive])dnl
47AS_VAR_POPDEF([gl_Flags])dnl
48AS_VAR_POPDEF([gl_Warn])dnl
49])
50
51# gl_UNKNOWN_WARNINGS_ARE_ERRORS
52# ------------------------------
53# Clang doesn't complain about unknown warning options unless one also
54# specifies -Wunknown-warning-option -Werror.  Detect this.
55AC_DEFUN([gl_UNKNOWN_WARNINGS_ARE_ERRORS],
56[AS_IF([test x${gl_unknown_warnings_are_errors+set} = x],
57  [gl_COMPILER_OPTION_IF([-Werror -Wunknown-warning-option],
58    [gl_unknown_warnings_are_errors='-Wunknown-warning-option -Werror'],
59    [gl_unknown_warnings_are_errors=])
60  ])
61])
62
63# gl_WARN_ADD(OPTION, [VARIABLE = WARN_CFLAGS],
64#             [PROGRAM = AC_LANG_PROGRAM()])
65# ---------------------------------------------
66# Adds parameter to WARN_CFLAGS if the compiler supports it when
67# compiling PROGRAM.  For example, gl_WARN_ADD([-Wparentheses]).
68#
69# If VARIABLE is a variable name, AC_SUBST it.
70AC_DEFUN([gl_WARN_ADD],
71[gl_UNKNOWN_WARNINGS_ARE_ERRORS
72gl_COMPILER_OPTION_IF([$1],
73  [gl_AS_VAR_APPEND(m4_if([$2], [], [[WARN_CFLAGS]], [[$2]]), [" $1"])],
74  [],
75  [$3])
76m4_ifval([$2],
77         [AS_LITERAL_IF([$2], [AC_SUBST([$2])])],
78         [AC_SUBST([WARN_CFLAGS])])dnl
79])
80
81# Local Variables:
82# mode: autoconf
83# End:
84