test POSIX ABI compatibility in libucontext itself, too

.gitignore

@@ -3,6 +3,7 @@ include/libucontext/bits.h
 examples/cooperative_threading
 test_libucontext
 test_libucontext_posix
+test_libucontext_bare_posixabi
 libucontext.a
 libucontext.so
 libucontext.so.*

Makefile

@@ -134,7 +134,7 @@ ${LIBUCONTEXT_POSIX_STATIC_NAME}_clean:
 libucontext_posix_obj_clean:
 	rm -f ${LIBUCONTEXT_POSIX_OBJ}
 
-check_clean: check_bare_clean check_posix_clean
+check_clean: check_bare_clean check_posix_clean check_bare_posixabi_clean
 
 check_bare_clean:
 	rm -f test_libucontext
@@ -142,6 +142,9 @@ check_bare_clean:
 check_posix_clean:
 	rm -f test_libucontext_posix
 
+check_bare_posixabi_clean:
+	rm -f test_libucontext_bare_posixabi
+
 docs_clean:
 	rm -f ${MANPAGES}
 
@@ -187,6 +190,16 @@ test_libucontext_posix: test_libucontext_posix.c ${LIBUCONTEXT_POSIX_NAME}
 	$(CC) -std=gnu99 -D_BSD_SOURCE ${CFLAGS} ${CPPFLAGS} $@.c -o $@ -L. -lucontext -lucontext_posix
 endif
 
+ifeq ($(EXPORT_UNPREFIXED),yes)
+check: check_libucontext_bare_posixabi
+
+check_libucontext_bare_posixabi: test_libucontext_bare_posixabi ${LIBUCONTEXT_SONAME}
+	env LD_LIBRARY_PATH=$(shell pwd) ./test_libucontext_bare_posixabi
+
+test_libucontext_bare_posixabi: test_libucontext_posix.c ${LIBUCONTEXT_NAME}
+	$(CC) -std=gnu99 -D_BSD_SOURCE ${CFLAGS} ${CPPFLAGS} test_libucontext_posix.c -o $@ -L. -lucontext
+endif
+
 check: test_libucontext ${LIBUCONTEXT_SONAME}
 	env LD_LIBRARY_PATH=$(shell pwd) ./test_libucontext