Introduce gnulib related files

This approach both gets us more up-to-date files right now and also
give us a cleaner documented approach for updating an maintaining
those file in the future.

The following command was employed:

  gnulib-tool --no-vc-files --source-base=gnulib --import havelib

gnulib was commit 1de03c03215d9919e6b9d768e86027a0a95ea10c
This is a slightly older to avoid the requirement for automake 1.14
(RHEL 7 is still 1.13.X) in the very latest gnulib.

Makefile.am

@@ -9,6 +9,7 @@ ACLOCAL_AMFLAGS = -I m4
 EXTRA_DIST= \
 autogen.sh \
 m4/Ovis-top.m4 \
+m4/gnulib-cache.m4 \
 SHA.txt \
 README.md
 
@@ -27,13 +28,13 @@ nobase_include_HEADERS = ovis-ldms-config.h
 docdir = $(datadir)/doc/@PACKAGE@
 dist_doc_DATA = COPYING gpl-2.0.txt
 
-SUBDIRS = lib ldms util
+SUBDIRS = lib ldms util gnulib
 
 # this definition of DIST_SUBDIRS is unusual. May decide to improve later.
 # For now, we ship as we expect to configure.
 # Perhaps all should be included all the time but we surround their
 # make content for dist with enable conditionals.
-DIST_SUBDIRS = lib ldms util
+DIST_SUBDIRS = lib ldms util gnulib
 # make dist _will_ fail for these unless we mod their .am files
 # so not included in dist.
 NODIST_SUBDIRS =

README.md

@@ -118,3 +118,21 @@ The following LDMS sampler plugins are considered unsupported. Use are your own
 * perfevent sampler
 * hweventpapi sampler
 * switchx
+
+## gnulib
+
+Some m4 files come from the gnulib project. To update these files, first checkout
+gnulib:
+
+  git clone git://git.savannah.gnu.org/gnulib.git
+
+There is no need to build or install the checked out code. The gnulib/gnulib-tool
+program works directly from the checked out tree.
+
+Next look at the comment at the top of the gnulib/Makefile.am file in the _ovis_
+source tree. That comment will tell you the full gnulib-tool command to repeat
+to install the latest versions of the currently selected components from gnulib.
+Additional gnulib components can be added to the command line as more macros are
+desired.
+
+After running gnulib-tool, check in the resulting changes.

configure.ac

@@ -10,6 +10,7 @@ AC_CONFIG_AUX_DIR(config)
 AM_CONFIG_HEADER(config.h)
 AC_REQUIRE_AUX_FILE([tap-driver.sh])
 AC_PROG_CC
+gl_EARLY
 AM_INIT_AUTOMAKE([foreign tar-pax])
 m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
 AX_PREFIX_CONFIG_H_G(ovis-ldms-config.h,,,[
@@ -35,6 +36,7 @@ AX_PREFIX_CONFIG_H_G(ovis-ldms-config.h,,,[
 #endif
 ])
 AM_PROG_LIBTOOL
+gl_INIT
 AC_LIB_RPATH
 
 dnl if LEX is not available, the configure still won't fail
@@ -907,6 +909,7 @@ lib/src/zap/test/Makefile
 lib/etc/Makefile
 lib/etc/ovis/Makefile
 lib/etc/ld.so.conf.d/Makefile
+gnulib/Makefile
 ldms/Makefile
 ldms/src/Makefile
 ldms/src/core/Makefile

gnulib/.gitignore

@@ -0,0 +1 @@
+/libgnu.a

gnulib/Makefile.am

@@ -0,0 +1,89 @@
+## DO NOT EDIT! GENERATED AUTOMATICALLY!
+## Process this file with automake to produce Makefile.in.
+# Copyright (C) 2002-2022 Free Software Foundation, Inc.
+#
+# This file is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This file is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this file.  If not, see <https://www.gnu.org/licenses/>.
+#
+# As a special exception to the GNU General Public License,
+# this file may be distributed as part of a program that
+# contains a configuration script generated by Autoconf, under
+# the same distribution terms as the rest of that program.
+#
+# Generated by gnulib-tool.
+# Reproduce by:
+# gnulib-tool --import \
+#  --lib=libgnu \
+#  --source-base=gnulib \
+#  --m4-base=m4 \
+#  --doc-base=doc \
+#  --tests-base=tests \
+#  --aux-dir=config \
+#  --no-conditional-dependencies \
+#  --no-libtool \
+#  --macro-prefix=gl \
+#  --no-vc-files \
+#  havelib
+
+AUTOMAKE_OPTIONS = 1.11 gnits
+
+SUBDIRS =
+noinst_HEADERS =
+noinst_LIBRARIES =
+noinst_LTLIBRARIES =
+EXTRA_DIST =
+BUILT_SOURCES =
+SUFFIXES =
+MOSTLYCLEANFILES = core *.stackdump
+MOSTLYCLEANDIRS =
+CLEANFILES =
+DISTCLEANFILES =
+MAINTAINERCLEANFILES =
+# No GNU Make output.
+
+AM_CPPFLAGS =
+AM_CFLAGS =
+
+noinst_LIBRARIES += libgnu.a
+
+libgnu_a_SOURCES =
+libgnu_a_CFLAGS = $(AM_CFLAGS) $(GL_CFLAG_GNULIB_WARNINGS)
+libgnu_a_LIBADD = $(gl_LIBOBJS)
+libgnu_a_DEPENDENCIES = $(gl_LIBOBJS)
+EXTRA_libgnu_a_SOURCES =
+
+## begin gnulib module havelib
+
+
+EXTRA_DIST += $(top_srcdir)/config/config.rpath
+
+## end   gnulib module havelib
+
+## begin gnulib module dummy
+
+libgnu_a_SOURCES += dummy.c
+
+## end   gnulib module dummy
+
+
+mostlyclean-local: mostlyclean-generic
+	@for dir in '' $(MOSTLYCLEANDIRS); do \
+	  if test -n "$$dir" && test -d $$dir; then \
+	    echo "rmdir $$dir"; rmdir $$dir; \
+	  fi; \
+	done; \
+	:
+distclean-local: distclean-gnulib-libobjs
+distclean-gnulib-libobjs:
+	-rm -f @gl_LIBOBJDEPS@
+maintainer-clean-local: distclean-gnulib-libobjs

gnulib/dummy.c

@@ -0,0 +1,31 @@
+/* A dummy file, to prevent empty libraries from breaking builds.
+   Copyright (C) 2004, 2007, 2009-2022 Free Software Foundation, Inc.
+
+   This file is in the public domain.  */
+
+/* Some systems, reportedly OpenBSD and Mac OS X, refuse to create
+   libraries without any object files.  You might get an error like:
+
+   > ar cru .libs/libgl.a
+   > ar: no archive members specified
+
+   Compiling this file, and adding its object file to the library, will
+   prevent the library from being empty.  */
+
+/* Some systems, such as Solaris with cc 5.0, refuse to work with libraries
+   that don't export any symbol.  You might get an error like:
+
+   > cc ... libgnu.a
+   > ild: (bad file) garbled symbol table in archive ../gllib/libgnu.a
+
+   Compiling this file, and adding its object file to the library, will
+   prevent the library from exporting no symbols.  */
+
+#ifdef __sun
+/* This declaration ensures that the library will export at least 1 symbol.  */
+int gl_dummy_symbol;
+#else
+/* This declaration is solely to ensure that after preprocessing
+   this file is never empty.  */
+typedef int dummy;
+#endif

m4/00gnulib.m4

@@ -0,0 +1,85 @@
+# 00gnulib.m4 serial 8
+dnl Copyright (C) 2009-2022 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl This file must be named something that sorts before all other
+dnl gnulib-provided .m4 files.  It is needed until the clang fix has
+dnl been included in Autoconf.
+
+# The following definitions arrange to use a compiler option
+# -Werror=implicit-function-declaration in AC_CHECK_DECL, when the
+# compiler is clang.  Without it, clang implicitly declares "known"
+# library functions in C mode, but not in C++ mode, which would cause
+# Gnulib to omit a declaration and thus later produce an error in C++
+# mode.  As of clang 9.0, these "known" functions are identified through
+# LIBBUILTIN invocations in the LLVM source file
+# llvm/tools/clang/include/clang/Basic/Builtins.def.
+# It's not possible to AC_REQUIRE the extra tests from AC_CHECK_DECL,
+# because AC_CHECK_DECL, like other Autoconf built-ins, is not supposed
+# to AC_REQUIRE anything: some configure.ac files have their first
+# AC_CHECK_DECL executed conditionally.  Therefore append the extra tests
+# to AC_PROG_CC.
+AC_DEFUN([gl_COMPILER_CLANG],
+[
+dnl AC_REQUIRE([AC_PROG_CC])
+  AC_CACHE_CHECK([whether the compiler is clang],
+    [gl_cv_compiler_clang],
+    [dnl Use _AC_COMPILE_IFELSE instead of AC_EGREP_CPP, to avoid error
+     dnl "circular dependency of AC_LANG_COMPILER(C)" if AC_PROG_CC has
+     dnl not yet been invoked.
+     _AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM([[
+           #ifdef __clang__
+           barfbarf
+           #endif
+           ]],[[]])
+        ],
+        [gl_cv_compiler_clang=no],
+        [gl_cv_compiler_clang=yes])
+    ])
+])
+AC_DEFUN([gl_COMPILER_PREPARE_CHECK_DECL],
+[
+dnl AC_REQUIRE([AC_PROG_CC])
+dnl AC_REQUIRE([gl_COMPILER_CLANG])
+  AC_CACHE_CHECK([for compiler option needed when checking for declarations],
+    [gl_cv_compiler_check_decl_option],
+    [if test $gl_cv_compiler_clang = yes; then
+       dnl Test whether the compiler supports the option
+       dnl '-Werror=implicit-function-declaration'.
+       save_ac_compile="$ac_compile"
+       ac_compile="$ac_compile -Werror=implicit-function-declaration"
+       dnl Use _AC_COMPILE_IFELSE instead of AC_COMPILE_IFELSE, to avoid a
+       dnl warning "AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS".
+       _AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]],[[]])],
+         [gl_cv_compiler_check_decl_option='-Werror=implicit-function-declaration'],
+         [gl_cv_compiler_check_decl_option=none])
+       ac_compile="$save_ac_compile"
+     else
+       gl_cv_compiler_check_decl_option=none
+     fi
+    ])
+  if test "x$gl_cv_compiler_check_decl_option" != xnone; then
+    ac_compile_for_check_decl="$ac_compile $gl_cv_compiler_check_decl_option"
+  else
+    ac_compile_for_check_decl="$ac_compile"
+  fi
+])
+dnl Redefine _AC_CHECK_DECL_BODY so that it references ac_compile_for_check_decl
+dnl instead of ac_compile.  If, for whatever reason, the override of AC_PROG_CC
+dnl in zzgnulib.m4 is inactive, use the original ac_compile.
+m4_define([_AC_CHECK_DECL_BODY],
+[  ac_save_ac_compile="$ac_compile"
+  if test -n "$ac_compile_for_check_decl"; then
+    ac_compile="$ac_compile_for_check_decl"
+  fi]
+m4_defn([_AC_CHECK_DECL_BODY])[  ac_compile="$ac_save_ac_compile"
+])
+
+# gl_00GNULIB
+# -----------
+# Witness macro that this file has been included.  Needed to force
+# Automake to include this file prior to all other gnulib .m4 files.
+AC_DEFUN([gl_00GNULIB])

m4/gnulib-cache.m4

@@ -0,0 +1,59 @@
+# Copyright (C) 2002-2022 Free Software Foundation, Inc.
+#
+# This file is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This file is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this file.  If not, see <https://www.gnu.org/licenses/>.
+#
+# As a special exception to the GNU General Public License,
+# this file may be distributed as part of a program that
+# contains a configuration script generated by Autoconf, under
+# the same distribution terms as the rest of that program.
+#
+# Generated by gnulib-tool.
+#
+# This file represents the specification of how gnulib-tool is used.
+# It acts as a cache: It is written and read by gnulib-tool.
+# In projects that use version control, this file is meant to be put under
+# version control, like the configure.ac and various Makefile.am files.
+
+
+# Specification in the form of a command-line invocation:
+# gnulib-tool --import \
+#  --lib=libgnu \
+#  --source-base=gnulib \
+#  --m4-base=m4 \
+#  --doc-base=doc \
+#  --tests-base=tests \
+#  --aux-dir=config \
+#  --no-conditional-dependencies \
+#  --no-libtool \
+#  --macro-prefix=gl \
+#  --no-vc-files \
+#  havelib
+
+# Specification in the form of a few gnulib-tool.m4 macro invocations:
+gl_LOCAL_DIR([])
+gl_MODULES([
+  havelib
+])
+gl_AVOID([])
+gl_SOURCE_BASE([gnulib])
+gl_M4_BASE([m4])
+gl_PO_BASE([])
+gl_DOC_BASE([doc])
+gl_TESTS_BASE([tests])
+gl_LIB([libgnu])
+gl_MAKEFILE_NAME([])
+gl_MACRO_PREFIX([gl])
+gl_PO_DOMAIN([])
+gl_WITNESS_C_MACRO([])
+gl_VC_FILES([false])