configure: Check for and explicitly link against -latomic

Some C libraries, such as uClibc, require an explicit link for some atomic
functions. Check for any libatomic, and explcily link it.

configure.ac

@@ -490,6 +490,11 @@ LIBS=$DLLIB
 AC_SEARCH_LIBS(pthread_create, pthread, [PTHREADLIB=$LIBS])
 AC_SUBST(PTHREADLIB)
 
+# uClibc requires explicit -latomic for __atomic_* operations
+LIBS=""
+AC_SEARCH_LIBS(__atomic_load, atomic, [ATOMICLIB=$LIBS])
+AC_SUBST(ATOMICLIB)
+
 LIBS=$saved_LIBS
 # ------------------------------------------------------
 

src/charon-cmd/Makefile.am

@@ -20,4 +20,4 @@ AM_CPPFLAGS = \
 charon_cmd_LDADD = \
 	$(top_builddir)/src/libstrongswan/libstrongswan.la \
 	$(top_builddir)/src/libcharon/libcharon.la \
-	-lm $(PTHREADLIB) $(DLLIB)
+	-lm $(PTHREADLIB) $(ATOMICLIB) $(DLLIB)

src/charon-nm/Makefile.am

@@ -21,4 +21,4 @@ AM_CFLAGS = \
 charon_nm_LDADD = \
 	$(top_builddir)/src/libstrongswan/libstrongswan.la \
 	$(top_builddir)/src/libcharon/libcharon.la \
-	-lm $(PTHREADLIB) $(DLLIB) ${nm_LIBS}
+	-lm $(PTHREADLIB) $(ATOMICLIB) $(DLLIB) ${nm_LIBS}

src/charon-systemd/Makefile.am

@@ -14,4 +14,5 @@ charon_systemd_CPPFLAGS = \
 charon_systemd_LDADD = \
 	$(top_builddir)/src/libstrongswan/libstrongswan.la \
 	$(top_builddir)/src/libcharon/libcharon.la \
-	$(systemd_LIBS) $(systemd_daemon_LIBS) $(systemd_journal_LIBS) -lm $(PTHREADLIB) $(DLLIB)
+	$(systemd_LIBS) $(systemd_daemon_LIBS) $(systemd_journal_LIBS) \
+	-lm $(PTHREADLIB) $(ATOMICLIB) $(DLLIB)

src/charon/Makefile.am

@@ -15,6 +15,6 @@ AM_CPPFLAGS = \
 charon_LDADD = \
 	$(top_builddir)/src/libstrongswan/libstrongswan.la \
 	$(top_builddir)/src/libcharon/libcharon.la \
-	-lm $(PTHREADLIB) $(DLLIB)
+	-lm $(PTHREADLIB) $(ATOMICLIB) $(DLLIB)
 
 EXTRA_DIST = Android.mk

src/conftest/Makefile.am

@@ -20,6 +20,6 @@ conftest_SOURCES = conftest.c conftest.h config.c config.h actions.c actions.h \
 conftest_LDADD = \
 	$(top_builddir)/src/libstrongswan/libstrongswan.la \
 	$(top_builddir)/src/libcharon/libcharon.la \
-	-lm $(PTHREADLIB) $(DLLIB)
+	-lm $(PTHREADLIB) $(ATOMICLIB) $(DLLIB)
 
 EXTRA_DIST = README

src/libcharon/Makefile.am

@@ -159,7 +159,7 @@ AM_LDFLAGS = \
 
 libcharon_la_LIBADD = \
   $(top_builddir)/src/libstrongswan/libstrongswan.la \
-  -lm $(PTHREADLIB) $(DLLIB) $(SOCKLIB)
+  -lm $(PTHREADLIB) $(ATOMICLIB) $(DLLIB) $(SOCKLIB)
 
 if USE_WINDOWS
   libcharon_la_LIBADD += -lws2_32

src/libfast/Makefile.am

@@ -22,4 +22,4 @@ endif
 
 libfast_la_LIBADD = \
 	$(top_builddir)/src/libstrongswan/libstrongswan.la \
-	-lfcgi $(clearsilver_LIBS) $(PTHREADLIB)
+	-lfcgi $(clearsilver_LIBS) $(PTHREADLIB) $(ATOMICLIB)

src/libstrongswan/Makefile.am

@@ -120,7 +120,9 @@ endif
 
 library.lo :	$(top_builddir)/config.status
 
-libstrongswan_la_LIBADD = $(DLLIB) $(BTLIB) $(SOCKLIB) $(RTLIB) $(BFDLIB) $(UNWINDLIB)
+libstrongswan_la_LIBADD = \
+	$(DLLIB) $(ATOMICLIB)  $(BTLIB) $(SOCKLIB) \
+	$(RTLIB) $(BFDLIB) $(UNWINDLIB)
 
 AM_CPPFLAGS = \
 	-I$(top_srcdir)/src/libstrongswan \

src/libstrongswan/tests/Makefile.am

@@ -12,7 +12,7 @@ libtest_la_CFLAGS = \
 libtest_la_LDFLAGS = @COVERAGE_LDFLAGS@
 libtest_la_LIBADD = \
   $(top_builddir)/src/libstrongswan/libstrongswan.la \
-  $(PTHREADLIB)
+  $(PTHREADLIB) $(ATOMICLIB)
 
 
 TESTS = tests

src/pki/Makefile.am

@@ -19,7 +19,7 @@ pki_SOURCES = pki.c pki.h command.c command.h \
 
 pki_LDADD = \
 	$(top_builddir)/src/libstrongswan/libstrongswan.la \
-	$(PTHREADLIB) $(DLLIB)
+	$(PTHREADLIB) $(ATOMICLIB) $(DLLIB)
 
 pki.o :	$(top_builddir)/config.status
 

src/starter/Makefile.am

@@ -34,7 +34,7 @@ starter_LDADD = \
 	$(top_builddir)/src/libstrongswan/libstrongswan.la \
 	$(top_builddir)/src/libcharon/libcharon.la \
 	libstarter.la \
-	$(SOCKLIB) $(PTHREADLIB)
+	$(SOCKLIB) $(PTHREADLIB) $(ATOMICLIB)
 
 EXTRA_DIST = keywords.txt ipsec.conf Android.mk
 MAINTAINERCLEANFILES = keywords.c

src/swanctl/Makefile.am

@@ -27,7 +27,7 @@ swanctl_SOURCES = \
 swanctl_LDADD = \
 	$(top_builddir)/src/libcharon/plugins/vici/libvici.la \
 	$(top_builddir)/src/libstrongswan/libstrongswan.la \
-	$(PTHREADLIB) $(DLLIB)
+	$(PTHREADLIB) $(ATOMICLIB) $(DLLIB)
 
 swanctl.o :		$(top_builddir)/config.status