[PATCH] bindings: cxx: link using the libtool archives

[orbea@riseup.net]

From: orbea <orbea@riseup.net>

When linking with internal dependencies that were built with libtool the
most reliable method is to use the libtool archive (.la) files.

When building with slibtool it fails when it doesn't find the -lgpiod
linker flag, but if libgpiod is already installed to the system it will
be built using the system version instead of the newly built libraries.

Gentoo issue: https://bugs.gentoo.org/913899

Signed-off-by: orbea <orbea@riseup.net>
---
 bindings/cxx/Makefile.am          | 2 +-
 bindings/cxx/examples/Makefile.am | 2 +-
 bindings/cxx/tests/Makefile.am    | 6 +++---
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/bindings/cxx/Makefile.am b/bindings/cxx/Makefile.am
index 1eafaa2..e2a89cf 100644
--- a/bindings/cxx/Makefile.am
+++ b/bindings/cxx/Makefile.am
@@ -24,8 +24,8 @@ libgpiodcxx_la_CXXFLAGS = -Wall -Wextra -g -std=gnu++17
 libgpiodcxx_la_CXXFLAGS += -fvisibility=hidden -I$(top_srcdir)/include/
 libgpiodcxx_la_CXXFLAGS += $(PROFILING_CFLAGS)
 libgpiodcxx_la_LDFLAGS = -version-info $(subst .,:,$(ABI_CXX_VERSION))
-libgpiodcxx_la_LDFLAGS += -lgpiod -L$(top_builddir)/lib
 libgpiodcxx_la_LDFLAGS += $(PROFILING_LDFLAGS)
+libgpiodcxx_la_LIBADD = $(top_builddir)/lib/libgpiod.la
 
 include_HEADERS = gpiod.hpp
 
diff --git a/bindings/cxx/examples/Makefile.am b/bindings/cxx/examples/Makefile.am
index 64ced20..eca4d64 100644
--- a/bindings/cxx/examples/Makefile.am
+++ b/bindings/cxx/examples/Makefile.am
@@ -3,7 +3,7 @@
 
 AM_CXXFLAGS = -I$(top_srcdir)/bindings/cxx/ -I$(top_srcdir)/include
 AM_CXXFLAGS += -Wall -Wextra -g -std=gnu++17
-AM_LDFLAGS = -lgpiodcxx -L$(top_builddir)/bindings/cxx/
+LDADD = $(top_builddir)/bindings/cxx/libgpiodcxx.la
 
 noinst_PROGRAMS = \
 	async_watch_line_value \
diff --git a/bindings/cxx/tests/Makefile.am b/bindings/cxx/tests/Makefile.am
index 02b5b6d..4d40d33 100644
--- a/bindings/cxx/tests/Makefile.am
+++ b/bindings/cxx/tests/Makefile.am
@@ -4,9 +4,9 @@
 AM_CXXFLAGS = -I$(top_srcdir)/bindings/cxx/ -I$(top_srcdir)/include
 AM_CXXFLAGS += -I$(top_srcdir)/tests/gpiosim/
 AM_CXXFLAGS += -Wall -Wextra -g -std=gnu++17 $(CATCH2_CFLAGS)
-AM_LDFLAGS = -lgpiodcxx -L$(top_builddir)/bindings/cxx/
-AM_LDFLAGS += -lgpiosim -L$(top_builddir)/tests/gpiosim/
-AM_LDFLAGS += -pthread
+AM_LDFLAGS = -pthread
+LDADD = $(top_builddir)/bindings/cxx/libgpiodcxx.la
+LDADD += $(top_builddir)/tests/gpiosim/libgiosim.la
 
 noinst_PROGRAMS = gpiod-cxx-test
 
-- 
2.43.2