[PATCH] Support building when fts and obstack aren't part of libc.

[Érico Nogueira]

- Make configure.ac test for fts and obstack availability;
- Add fts and obstack ldflags to all files that need them;
- Add missing argp ldflags to programs in debuginfod/.

Signed-off-by: Érico Rolim <erico.erc@gmail.com>
---

This is the start of a series of patches that can enable elfutils to be
built on musl-based distros out of the box.

I will send them as separate mails, since upstreaming any of the
necessary patches should still help with avoiding duplication across
distros as well as lowering the maintenance burden.

 ChangeLog              |  4 ++++
 configure.ac           | 54 ++++++++++++++++++++++++++++++++++++++++++
 debuginfod/Makefile.am |  6 ++---
 libdw/Makefile.am      |  2 +-
 src/Makefile.am        |  6 ++---
 5 files changed, 65 insertions(+), 7 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 72e8397c..10587886 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2020-10-25  Érico N. Rolim  <erico.erc@gmail.com>
+
+	* configure.ac: Check for fts and obstack from outside libc.
+
 2020-10-01  Frank Ch. Eigler  <fche@redhat.com>
 
 	PR25461
diff --git a/configure.ac b/configure.ac
index 973409f1..628e7a74 100644
--- a/configure.ac
+++ b/configure.ac
@@ -542,6 +542,60 @@ else
 fi
 AC_SUBST([argp_LDADD])
 
+dnl Check if we have fts available from our libc
+AC_LINK_IFELSE(
+	[AC_LANG_PROGRAM(
+		[#if !defined(__x86_64__)
+		#undef  _FILE_OFFSET_BITS
+		#define _FILE_OFFSET_BITS 32
+		#endif
+		#include <fts.h>],
+		[FTS* fts = 0; return fts_close(fts); return 0;]
+		)],
+	[libc_has_fts="true"],
+	[libc_has_fts="false"]
+)
+
+dnl If our libc doesn't provide fts, then test for libfts
+if test "$libc_has_fts" = "false" ; then
+	AC_MSG_WARN("libc does not have fts")
+	AC_CHECK_LIB([fts], [fts_close], [have_fts="true"], [have_fts="false"])
+
+	if test "$have_fts" = "false"; then
+		AC_MSG_ERROR("no libfts found")
+	else
+		fts_LDADD="-lfts"
+	fi
+else
+	fts_LDADD=""
+fi
+AC_SUBST([fts_LDADD])
+
+dnl Check if we have obstack available from our libc
+AC_LINK_IFELSE(
+	[AC_LANG_PROGRAM(
+		[#include <obstack.h>],
+		[_obstack_begin(0, 0, 0, NULL, NULL); return 0;]
+		)],
+	[libc_has_obstack="true"],
+	[libc_has_obstack="false"]
+)
+
+dnl If our libc doesn't provide obstack, then test for libobstack
+if test "$libc_has_obstack" = "false" ; then
+	AC_MSG_WARN("libc does not have obstack")
+	AC_CHECK_LIB([obstack], [_obstack_begin], [have_obstack="true"], [have_obstack="false"])
+
+	if test "$have_obstack" = "false"; then
+		AC_MSG_ERROR("no libobstack found")
+	else
+		obstack_LDADD="-lobstack"
+	fi
+else
+	obstack_LDADD=""
+fi
+AC_SUBST([obstack_LDADD])
+
 dnl The directories with content.
 
 dnl Documentation.
diff --git a/debuginfod/Makefile.am b/debuginfod/Makefile.am
index 01985600..bdb6d8a4 100644
--- a/debuginfod/Makefile.am
+++ b/debuginfod/Makefile.am
@@ -71,10 +71,10 @@ bin_PROGRAMS += debuginfod-find
 endif
 
 debuginfod_SOURCES = debuginfod.cxx
-debuginfod_LDADD = $(libdw) $(libelf) $(libeu) $(libdebuginfod) $(libmicrohttpd_LIBS) $(sqlite3_LIBS) $(libarchive_LIBS) -lpthread -ldl
+debuginfod_LDADD = $(libdw) $(libelf) $(libeu) $(libdebuginfod) $(argp_LDADD) $(fts_LDADD) $(libmicrohttpd_LIBS) $(sqlite3_LIBS) $(libarchive_LIBS) -lpthread -ldl
 
 debuginfod_find_SOURCES = debuginfod-find.c
-debuginfod_find_LDADD = $(libdw) $(libelf) $(libeu) $(libdebuginfod)
+debuginfod_find_LDADD = $(libdw) $(libelf) $(libeu) $(libdebuginfod) $(argp_LDADD) $(fts_LDADD)
 
 if LIBDEBUGINFOD
 noinst_LIBRARIES = libdebuginfod.a
@@ -98,7 +98,7 @@ libdebuginfod_so_LIBS = libdebuginfod_pic.a
 if DUMMY_LIBDEBUGINFOD
 libdebuginfod_so_LDLIBS =
 else
-libdebuginfod_so_LDLIBS = $(libcurl_LIBS)
+libdebuginfod_so_LDLIBS = $(libcurl_LIBS) $(fts_LDADD)
 endif
 libdebuginfod.so$(EXEEXT): $(srcdir)/libdebuginfod.map $(libdebuginfod_so_LIBS)
 	$(AM_V_CCLD)$(LINK) $(dso_LDFLAGS) -o $@ \
diff --git a/libdw/Makefile.am b/libdw/Makefile.am
index 33b5838d..af30825b 100644
--- a/libdw/Makefile.am
+++ b/libdw/Makefile.am
@@ -109,7 +109,7 @@ libdw_so_LIBS = ../libebl/libebl_pic.a ../backends/libebl_backends_pic.a \
 		../libcpu/libcpu_pic.a libdw_pic.a ../libdwelf/libdwelf_pic.a \
 		../libdwfl/libdwfl_pic.a
 libdw_so_DEPS = ../lib/libeu.a ../libelf/libelf.so
-libdw_so_LDLIBS = $(libdw_so_DEPS) -ldl -lz $(argp_LDADD) $(zip_LIBS) -pthread
+libdw_so_LDLIBS = $(libdw_so_DEPS) -ldl -lz $(argp_LDADD) $(fts_LDADD) $(obstack_LDADD) $(zip_LIBS) -pthread
 libdw_so_SOURCES =
 libdw.so$(EXEEXT): $(srcdir)/libdw.map $(libdw_so_LIBS) $(libdw_so_DEPS)
 	$(AM_V_CCLD)$(LINK) $(dso_LDFLAGS) -o $@ \
diff --git a/src/Makefile.am b/src/Makefile.am
index e462e7d7..cade82ff 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -69,7 +69,7 @@ ar_no_Wstack_usage = yes
 unstrip_no_Wstack_usage = yes
 
 readelf_LDADD = $(libdw) $(libebl) $(libelf) $(libeu) $(argp_LDADD)
-nm_LDADD = $(libdw) $(libebl) $(libelf) $(libeu) $(argp_LDADD) \
+nm_LDADD = $(libdw) $(libebl) $(libelf) $(libeu) $(argp_LDADD) $(obstack_LDADD) \
 	   $(demanglelib)
 size_LDADD = $(libelf) $(libeu) $(argp_LDADD)
 strip_LDADD = $(libebl) $(libelf) $(libdw) $(libeu) $(argp_LDADD)
@@ -78,9 +78,9 @@ findtextrel_LDADD = $(libdw) $(libelf) $(libeu) $(argp_LDADD)
 addr2line_LDADD = $(libdw) $(libelf) $(libeu) $(argp_LDADD) $(demanglelib)
 elfcmp_LDADD = $(libebl) $(libdw) $(libelf) $(libeu) $(argp_LDADD)
 objdump_LDADD  = $(libasm) $(libebl) $(libdw) $(libelf) $(libeu) $(argp_LDADD)
-ranlib_LDADD = libar.a $(libelf) $(libeu) $(argp_LDADD)
+ranlib_LDADD = libar.a $(libelf) $(libeu) $(argp_LDADD) $(obstack_LDADD)
 strings_LDADD = $(libelf) $(libeu) $(argp_LDADD)
-ar_LDADD = libar.a $(libelf) $(libeu) $(argp_LDADD)
+ar_LDADD = libar.a $(libelf) $(libeu) $(argp_LDADD) $(obstack_LDADD)
 unstrip_LDADD = $(libebl) $(libelf) $(libdw) $(libeu) $(argp_LDADD)
 stack_LDADD = $(libebl) $(libelf) $(libdw) $(libeu) $(argp_LDADD) $(demanglelib)
 elfcompress_LDADD = $(libebl) $(libelf) $(libdw) $(libeu) $(argp_LDADD)
-- 
2.28.0