[PATCH 1/2] Allow building the libraries without argp

[Ulf Hermann <ulf dot hermann at qt dot io>]

If argp is unavailable we cannot build tests, tools and argp-std.c in
libdwfl. We can still build the libraries, though. Test for this and
provide a dwfl_standard_argp() that just returns NULL and only gets
compiled if argp is missing.

Signed-off-by: Ulf Hermann <ulf.hermann@qt.io>
---
 ChangeLog            | 12 ++++++++++++
 Makefile.am          |  6 +++++-
 configure.ac         | 31 +++++++++++++++++++++----------
 lib/ChangeLog        |  7 +++++++
 lib/Makefile.am      | 10 +++++++---
 libdwfl/ChangeLog    |  6 ++++++
 libdwfl/Makefile.am  |  8 +++++++-
 libdwfl/argp-dummy.c | 38 ++++++++++++++++++++++++++++++++++++++
 8 files changed, 103 insertions(+), 15 deletions(-)
 create mode 100644 libdwfl/argp-dummy.c

diff --git a/ChangeLog b/ChangeLog
index 15b36dd..e93d05f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2017-02-20  Ulf Hermann  <ulf.hermann@qt.io>
+
+	* configure.ac: Don't abort if no argp is found. Only print a
+	warning, rename have_argp to with_argp (like lzma, bzip2 ..),
+	and use "yes"/"no" as values, as we do for other variables.
+	* configure.ac: Set with_argp also if argp is in libargp, and
+	pass it on as AM_CONDITIONAL ARGP.
+	* configure.ac: Skip configuration of src and tests if
+	argp is not available.
+	* Makefile.am (SUBDIRS): Skip src and tests if argp is not
+	available.
+
 2017-02-17  Ulf Hermann  <ulf.hermann@qt.io>
 
 	* configure.ac: Define HAVE_MEMPCPY if mempcpy is available.
diff --git a/Makefile.am b/Makefile.am
index 2ff444e..59225cc 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -28,7 +28,11 @@ pkginclude_HEADERS = version.h
 
 # Add doc back when we have some real content.
 SUBDIRS = config m4 lib libelf libebl libdwelf libdwfl libdw libcpu libasm \
-	  backends src po tests
+	  backends po
+
+if ARGP
+SUBDIRS += src tests
+endif
 
 EXTRA_DIST = elfutils.spec GPG-KEY NOTES CONTRIBUTING \
 	     COPYING COPYING-GPLV2 COPYING-LGPLV3
diff --git a/configure.ac b/configure.ac
index 303bf4d..60b8796 100644
--- a/configure.ac
+++ b/configure.ac
@@ -367,24 +367,27 @@ AC_LINK_IFELSE(
 		[#include <argp.h>],
 		[int argc=1; char *argv[]={"test"}; argp_parse(0,argc,&argv,0,0,0); return 0;]
 		)],
-	[libc_has_argp="true"],
-	[libc_has_argp="false"]
+	[libc_has_argp="yes"],
+	[libc_has_argp="no"]
 )
 
 dnl If our libc doesn't provide argp, then test for libargp
-if test "$libc_has_argp" = "false" ; then
+if test "$libc_has_argp" = "no" ; then
 	AC_MSG_WARN("libc does not have argp")
-	AC_CHECK_LIB([argp], [argp_parse], [have_argp="true"], [have_argp="false"])
+	AC_CHECK_LIB([argp], [argp_parse], [with_argp="yes"], [with_argp="no"])
 
-	if test "$have_argp" = "false"; then
-		AC_MSG_ERROR("no libargp found")
+	if test "$with_argp" = "no"; then
+		AC_MSG_WARN("no libargp found")
+		argp_LDADD=""
 	else
 		argp_LDADD="-largp"
 	fi
 else
+	with_argp="yes"
 	argp_LDADD=""
 fi
 AC_SUBST([argp_LDADD])
+AM_CONDITIONAL(ARGP, [test "x$with_argp" = "xyes"])
 
 dnl Check if we have <linux/bpf.h> for EM_BPF disassembly.
 AC_CHECK_HEADERS(linux/bpf.h)
@@ -424,12 +427,19 @@ AC_CONFIG_FILES([libasm/Makefile])
 dnl CPU-specific backend libraries.
 AC_CONFIG_FILES([backends/Makefile])
 
-dnl Tools.
-AC_CONFIG_FILES([src/Makefile po/Makefile.in])
+dnl Translations
+AC_CONFIG_FILES([po/Makefile.in])
 
-dnl Test suite.
 AM_CONDITIONAL(STANDALONE, false)dnl Used in tests/Makefile.am, which see.
-AC_CONFIG_FILES([tests/Makefile])
+if test "x$with_argp" = "xyes"; then
+	dnl Tools.
+	AC_CONFIG_FILES([src/Makefile])
+
+	dnl Test suite.
+	AC_CONFIG_FILES([tests/Makefile])
+else
+	AC_MSG_WARN("Not building tools or tests.")
+fi
 
 dnl pkgconfig files
 AC_CONFIG_FILES([config/libelf.pc config/libdw.pc])
@@ -546,6 +556,7 @@ AC_MSG_NOTICE([
     build arch                         : ${ac_cv_build}
 
   RECOMMENDED FEATURES (should all be yes)
+    argp support                       : ${with_argp}
     gzip support                       : ${with_zlib}
     bzip2 support                      : ${with_bzlib}
     lzma/xz support                    : ${with_lzma}
diff --git a/lib/ChangeLog b/lib/ChangeLog
index dcd20e1..c97537e 100644
--- a/lib/ChangeLog
+++ b/lib/ChangeLog
@@ -1,3 +1,10 @@
+2017-02-20  Ulf Hermann  <ulf.hermann@qt.io>
+
+	* Makefile.am (libeu_a_SOURCES): Skip printversion.c and
+	color.c if argp is not available.
+	(noinst_HEADERS): Skip printversion.h and color.h if argp is
+	not available.
+
 2017-02-17  Ulf Hermann  <ulf.hermann@qt.io>
 
 	* system.h: Make mempcpy a function.
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 63738fd..93a965c 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -34,17 +34,21 @@ AM_CPPFLAGS += -I$(srcdir)/../libelf
 noinst_LIBRARIES = libeu.a
 
 libeu_a_SOURCES = xstrdup.c xstrndup.c xmalloc.c next_prime.c \
-		  crc32.c crc32_file.c md5.c sha1.c \
-		  color.c printversion.c
+		  crc32.c crc32_file.c md5.c sha1.c
 
 noinst_HEADERS = fixedsizehash.h libeu.h system.h dynamicsizehash.h list.h \
-		 md5.h sha1.h eu-config.h color.h printversion.h
+		 md5.h sha1.h eu-config.h
 EXTRA_DIST = dynamicsizehash.c
 
 if !HAVE_MEMPCPY
 libeu_a_SOURCES += mempcpy.c
 endif
 
+if ARGP
+libeu_a_SOURCES += printversion.c color.c
+noinst_HEADERS += printversion.h color.h
+endif
+
 if !GPROF
 xmalloc_CFLAGS = -ffunction-sections
 endif
diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index 4c9f4f6..570c66f 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,3 +1,9 @@
+2017-02-20  Ulf Hermann  <ulf.hermann@qt.io>
+
+	* argp-dummy.c: New file.
+	* Makefile.am (libdwfl_a_SOURCES): If argp is not available,
+	compile argp-dummy.c rather than argp-std.c.
+
 2017-02-15  Ulf Hermann  <ulf.hermann@qt.io>
 
 	* linux-kernel-modules.c: Include system.h.
diff --git a/libdwfl/Makefile.am b/libdwfl/Makefile.am
index 89ca92e..69ea431 100644
--- a/libdwfl/Makefile.am
+++ b/libdwfl/Makefile.am
@@ -46,7 +46,7 @@ libdwfl_a_SOURCES = dwfl_begin.c dwfl_end.c dwfl_error.c dwfl_version.c \
 		    dwfl_module_info.c dwfl_getmodules.c dwfl_getdwarf.c \
 		    dwfl_module_getdwarf.c dwfl_module_getelf.c \
 		    dwfl_validate_address.c \
-		    argp-std.c find-debuginfo.c \
+		    find-debuginfo.c \
 		    dwfl_build_id_find_elf.c \
 		    dwfl_build_id_find_debuginfo.c \
 		    linux-kernel-modules.c linux-proc-maps.c \
@@ -71,6 +71,12 @@ libdwfl_a_SOURCES = dwfl_begin.c dwfl_end.c dwfl_error.c dwfl_version.c \
 		    linux-pid-attach.c linux-core-attach.c dwfl_frame_regs.c \
 		    gzip.c
 
+if ARGP
+libdwfl_a_SOURCES += argp-std.c
+else
+libdwfl_a_SOURCES += argp-dummy.c
+endif
+
 if BZLIB
 libdwfl_a_SOURCES += bzip2.c
 endif
diff --git a/libdwfl/argp-dummy.c b/libdwfl/argp-dummy.c
new file mode 100644
index 0000000..7d561c0
--- /dev/null
+++ b/libdwfl/argp-dummy.c
@@ -0,0 +1,38 @@
+/* Dummy argp argument parser.
+   Copyright (C) 2017 The Qt Company Ltd.
+   This file is part of elfutils.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of either
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at
+       your option) any later version
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at
+       your option) any later version
+
+   or both in parallel, as here.
+
+   elfutils 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 copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#include "libdwflP.h"
+
+/* If argp is unavailable we cannot implement this. It is not really
+   libdwfl's job to do argument parsing, though. */
+
+const struct argp *
+dwfl_standard_argp (void)
+{
+  return NULL;
+}
-- 
2.1.4