1 files changed, 63 insertions, 0 deletions

diff --git a/m4/mhd_check_add_cc_cflag.m4 b/m4/mhd_check_add_cc_cflag.m4
new file mode 100644
index 00000000..0d110e8c
--- /dev/null
+++ b/m4/mhd_check_add_cc_cflag.m4
@@ -0,0 +1,63 @@
+# SYNOPSIS
+#
+#   MHD_CHECK_ADD_CC_CFLAG([FLAG-TO-TEST], [VARIABLE-TO-EXTEND],
+#                          [ACTION-IF-SUPPORTED], [ACTION-IF-NOT-SUPPORTED])
+#
+# DESCRIPTION
+#
+#   This macro checks whether the specific compiler flag is supported.
+#   The check is performing by appending FLAG-TO-TEST to the value of
+#   VARIABLE-TO-EXTEND (CFLAGS if not specified), then prepending result to
+#   CFLAGS (unless VARIABLE-TO-EXTEND is CFLAGS), and then performing compile
+#   and link test. If test succeed without warnings, then the flag is added to
+#   VARIABLE-TO-EXTEND. Otherwise, if compile and link without test flag cannot
+#   be done without any warning, the flag is considered to be unsuppoted.
+#
+#   Example usage:
+#
+#     MHD_CHECK_ADD_CC_CFLAG([-Wshadow], [additional_CFLAGS])
+#
+#
+# LICENSE
+#
+#   Copyright (c) 2022 Karlson2k (Evgeny Grin) <k2k@narod.ru>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 1
+
+AC_DEFUN([MHD_CHECK_ADD_CC_CFLAG],[dnl
+_MHD_CHECK_ADD_CC_XFLAG([$1],[$2],[$3],[$4],[[CFLAGS]])dnl
+])
+
+
+# SYNOPSIS
+#
+#   _MHD_CHECK_ADD_CC_XFLAG([FLAG-TO-TEST], [VARIABLE-TO-EXTEND],
+#                           [ACTION-IF-SUPPORTED], [ACTION-IF-NOT-SUPPORTED],
+#                           [CFLAGS|LDFLAGS])
+#
+AC_DEFUN([_MHD_CHECK_ADD_CC_XFLAG],[dnl
+  AC_PREREQ([2.64])dnl for AS_VAR_IF, m4_ifnblank, m4_default
+  AC_LANG_ASSERT([C])dnl
+  m4_ifblank([$1], [m4_fatal([First macro argument must not be empty])])dnl
+  m4_bmatch(_mhd_norm_expd([$1]), [\s],dnl
+            [m4_fatal([First macro argument must not contain whitespaces])])dnl
+  m4_bmatch(_mhd_norm_expd([$2]), [\s],dnl
+            [m4_fatal([Second macro argument must not contain whitespaces])])dnl
+  m4_bmatch([$1], [\$], [m4_fatal([$0: First macro argument must not contain '$'])])dnl
+  m4_bmatch([$2], [\$], [m4_fatal([$0: Second macro argument must not contain '$'])])dnl
+  m4_bmatch(_mhd_norm_expd([$5]), [^\(CFLAGS\|LDFLAGS\)$],[],dnl
+   [m4_fatal([$0: Fifth macro argument must be either 'CFLAGS' or 'LDFLAGS; ']_mhd_norm_expd([$5])[' is not supported])])dnl
+  m4_ifnblank([$2],
+    [_MHD_CHECK_CC_XFLAG([$1], [$2],
+      [MHD_APPEND_FLAG_TO_VAR(_mhd_norm_expd([$2]),_mhd_norm_expd([$1]))
+       $3],[$4],[$5])],
+    [_MHD_CHECK_CC_XFLAG([$1],_mhd_norm_expd([$5]),
+      [MHD_APPEND_FLAG_TO_VAR(_mhd_norm_expd([$5]),_mhd_norm_expd([$1]))
+       $3],[$4],[$5])]
+  )
+])